Name: intracerebroventricular treatment with resiniferatoxin and pain tests in mice
Uploaded: 2020-09-02T12:30:00
Description: Watch this Scientific Journal Video about Intracerebroventricular Treatment with Resiniferatoxin and Pain Tests in Mice at JoVE.com

All of the experimental protocols used here were approved by the Animal Care and Use Committee of Musashino University. Male ddY mice (SLC, Shizuoka, Japan) were kept for at least 7 days under a 12-h light/dark cycle before experiments with water and food ad libitum. 5- or 6-week-old mice were used for the experiments.
1. Preparation of Drugs
<ol>
	<li>RTX 
	NOTE: Alcoholic RTX solution can cause severe skin burns and eye damage. Make sure to use rubber gloves and glass...

<ol>
	<li>Cavanaugh, D. J., Chesler, A. T., Braz, J. M., Shah, N. M., Julius, D., Basbaum, A. I. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Restriction+of+transient+receptor+potential+vanilloid-1+to+the+peptidergic+subset+of+primary+afferent+neurons+follows+its+developmental+downregulation+in+nonpeptidergic+neurons.">Restriction of transient receptor potential vanilloid-1 to the peptidergic subset of primary afferent neurons follows its developmental downregulation in nonpeptidergic neurons.</a> J Neurosci. 31 (28), 10119-10127 (2011).</li><li>Caterina, M. J., Schumacher, M. A., Tominaga, M., Rosen, T. A., Levine, J. D., Julius, D. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=The+capsaicin+receptor:+a+heat-activated+ion+channel+in+the+pain+pathway.">The capsaicin receptor: a heat-activated ion channel in the pain pathway.</a> Nature. 389 (6653), 816-824 (1997).</li><li>Caterina, M. J., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Impaired+nociception+and+pain+sensation+in+mice+lacking+the+capsaicin+receptor.">Impaired nociception and pain sensation in mice lacking the capsaicin receptor.</a> Science. 288 (5464), 306-313 (2000).</li><li>Starowicz, K., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Tonic+endovanilloid+facilitation+of+glutamate+release+in+brainstem+descending+antinociceptive+pathways.">Tonic endovanilloid facilitation of glutamate release in brainstem descending antinociceptive pathways.</a> The Journal of neuroscience the official journal of the Society for Neuroscience. 27 (50), 13739-13749 (2007).</li><li>Gavva, N. R., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=The+vanilloid+receptor+TRPV1+is+tonically+activated+in+vivo+and+involved+in+body+temperature+regulation.">The vanilloid receptor TRPV1 is tonically activated in vivo and involved in body temperature regulation.</a> The Journal of neuroscience the official journal of the Society for Neuroscience. 27 (13), 3366-3374 (2007).</li><li>Marsch, R., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Reduced+anxiety,+conditioned+fear,+and+hippocampal+long-term+potentiation+in+transient+receptor+potential+vanilloid+type+1+receptor-deficient+mice.">Reduced anxiety, conditioned fear, and hippocampal long-term potentiation in transient receptor potential vanilloid type 1 receptor-deficient mice.</a> Journal of Neuroscience. 27 (4), 832-839 (2007).</li><li>Tzavara, E. T., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Endocannabinoids+activate+transient+receptor+potential+vanilloid+1+receptors+to+reduce+hyperdopaminergia-related+hyperactivity:+Therapeutic+implications.">Endocannabinoids activate transient receptor potential vanilloid 1 receptors to reduce hyperdopaminergia-related hyperactivity: Therapeutic implications.</a> Biological Psychiatry. 59 (6), 508-515 (2006).</li><li>Naz&#305;ro&#287;lu, M., &#214;vey, &. #. 3. 0. 4. ;. S. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Involvement+of+apoptosis+and+calcium+accumulation+through+TRPV1+channels+in+neurobiology+of+epilepsy.">Involvement of apoptosis and calcium accumulation through TRPV1 channels in neurobiology of epilepsy.</a> Neuroscience. 293, 55-66 (2015).</li><li>Mallet, C., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=TRPV1+in+brain+is+involved+in+acetaminophen-induced+antinociception.">TRPV1 in brain is involved in acetaminophen-induced antinociception.</a> PloS one. 5 (9), 1-11 (2010).</li><li>Barri&#232;re, D. A., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Fatty+acid+amide+hydrolase-dependent+generation+of+antinociceptive+drug+metabolites+acting+on+TRPV1+in+the+brain.">Fatty acid amide hydrolase-dependent generation of antinociceptive drug metabolites acting on TRPV1 in the brain.</a> PloS one. 8 (8), e70690 (2013).</li><li>Jancs&#243;, G., Kiraly, E., Jancs&#243;-G&#225;bor, A. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Pharmacologically+induced+selective+degeneration+of+chemosensitive+primary+sensory+neurones.">Pharmacologically induced selective degeneration of chemosensitive primary sensory neurones.</a> Nature. 270 (5639), 741-743 (1977).</li><li>Szallasi, A., Blumberg, P. M. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Vanilloid+receptor+loss+in+rat+sensory+ganglia+associated+with+long+term+desensitization+to+resiniferatoxin.">Vanilloid receptor loss in rat sensory ganglia associated with long term desensitization to resiniferatoxin.</a> Neuroscience Letters. 140 (1), 51-54 (1992).</li><li>Cavanaugh, D. J., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Distinct+subsets+of+unmyelinated+primary+sensory+fibers+mediate+behavioral+responses+to+noxious+thermal+and+mechanical+stimuli.">Distinct subsets of unmyelinated primary sensory fibers mediate behavioral responses to noxious thermal and mechanical stimuli.</a> Proceedings of the National Academy of Sciences of the United States of America. 106 (22), 9075-9080 (2009).</li><li>Jeffry, J. A., Yu, S. Q., Sikand, P., Parihar, A., Evans, M. S., Premkumar, L. S. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Selective+targeting+of+TRPV1+expressing+sensory+nerve+terminals+in+the+spinal+cord+for+long+lasting+analgesia.">Selective targeting of TRPV1 expressing sensory nerve terminals in the spinal cord for long lasting analgesia.</a> PLoS ONE. 4 (9), e7021 (2009).</li><li>Jancs&#243;, G. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Intracisternal+capsaicin:+selective+degeneration+of+chemosensitive+primary+sensory+afferents+in+the+adult+rat.">Intracisternal capsaicin: selective degeneration of chemosensitive primary sensory afferents in the adult rat.</a> Neuroscience letters. 27 (1), 41-45 (1981).</li><li>Gamse, R., Saria, A., Lundberg, J. M., Theodorsson-Norheim, E. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Behavioral+and+neurochemical+changes+after+intracisternal+capsaicin+treatment+of+the+guinea+pig.">Behavioral and neurochemical changes after intracisternal capsaicin treatment of the guinea pig.</a> Neuroscience Letters. 64 (3), 287-292 (1986).</li><li>Neubert, J. K., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Characterization+of+mouse+orofacial+pain+and+the+effects+of+lesioning+TRPV1-expressing+neurons+on+operant+behavior.">Characterization of mouse orofacial pain and the effects of lesioning TRPV1-expressing neurons on operant behavior.</a> Molecular pain. 4, 43 (2008).</li><li>Karai, L., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Deletion+of+vanilloid+receptor+1-expressing+primary+afferent+neurons+for+pain+control.">Deletion of vanilloid receptor 1-expressing primary afferent neurons for pain control.</a> The Journal of clinical investigation. 113 (9), 1344-1352 (2004).</li><li>Fukushima, A., Mamada, K., Iimura, A., Ono, H. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Supraspinal-selective+TRPV1+desensitization+induced+by+intracerebroventricular+treatment+with+resiniferatoxin.">Supraspinal-selective TRPV1 desensitization induced by intracerebroventricular treatment with resiniferatoxin.</a> Scientific reports. 7 (1), 12452 (2017).</li><li>Haley, T. J., McCormick, W. G. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Pharmacological+effects+produced+by+intracerebral+injection+of+drugs+in+the+conscious+mouse.">Pharmacological effects produced by intracerebral injection of drugs in the conscious mouse.</a> British journal of pharmacology and chemotherapy. 12 (1), 12-15 (1957).</li><li>Tj&#248;lsen, A., Berge, O. G., Hunskaar, S., Rosland, J. H., Hole, K. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=The+formalin+test:+an+evaluation+of+the+method.">The formalin test: an evaluation of the method.</a> Pain. 51 (1), 5-17 (1992).</li><li>Ohsawa, M., Miyabe, Y., Katsu, H., Yamamoto, S., Ono, H. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Identification+of+the+sensory+nerve+fiber+responsible+for+lysophosphatidic+acid-induced+allodynia+in+mice.">Identification of the sensory nerve fiber responsible for lysophosphatidic acid-induced allodynia in mice.</a> Neuroscience. 247, 65-74 (2013).</li><li>Tanabe, M., Tokuda, Y., Takasu, K., Ono, K., Honda, M., Ono, H. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=The+synthetic+TRH+analogue+taltirelin+exerts+modality-specific+antinociceptive+effects+via+distinct+descending+monoaminergic+systems.">The synthetic TRH analogue taltirelin exerts modality-specific antinociceptive effects via distinct descending monoaminergic systems.</a> British journal of pharmacology. 150 (4), 403-414 (2007).</li><li>Ono, H., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Reduction+in+sympathetic+nerve+activity+as+a+possible+mechanism+for+the+hypothermic+effect+of+oseltamivir,+an+anti-influenza+virus+drug,+in+normal+mice.">Reduction in sympathetic nerve activity as a possible mechanism for the hypothermic effect of oseltamivir, an anti-influenza virus drug, in normal mice.</a> Basic &amp; clinical pharmacology &amp; toxicology. 113 (1), 25-30 (2013).</li><li>Kauer, J. A., Gibson, H. E. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Hot+flash:+TRPV+channels+in+the+brain.">Hot flash: TRPV channels in the brain.</a> Trends in neurosciences. 32 (4), 215-224 (2009).</li></ol>

The most critical step in these experiments is the success of the i.c.v. injection. The i.c.v. injection technique used here is quite simple but requires some practice. Prior to experiments, practice with dyes (e.g. 0.5% trypan blue in saline) is recommended. If the injection is performed correctly, a needle mark should be evident on the coronal suture and the injected dye should be present in the contralateral ventricle and the third ventricle. Moreover, forcible insertion should be avoided during injection. If the need...

Animals receive various physical and chemical stimuli from their environment through sensors on the peripheral nerves. The transient receptor potential vanilloid type 1 (TRPV1) is one of the thermosensitive, nonselective cation channels that act as heat sensors1,2, and activation and/or modulation of TRPV1 is known to be a key step for nociception in both normal and inflammatory contexts3. Although the overall expression pattern is controversial, expression of TRPV1 has also been suggested in supraspinal regions, being involved in various brain activities (including nociception4, thermoregulation5, anxiety6, attention deficit hyperactivity disorder7, and epilepsy8). Moreover, it has recently been suggested that acetaminophen, a widely used painkiller, mediates the activation of central TRPV1 to elicit its analgesic action9,10.
Administration of excess TRPV1 agonist including capsaicin and resiniferatoxin (RTX) to animals leads to the death of TRPV1-positive neurons and long-lasting desensitization to TRPV1 agonists11,12. Combined with the local application (intrathecal13,14, intracisternal15,16,17, and intraganglional18), this chemical ablation approach has provided an alternative way to investigate the physiological functions of TRPV1. We have recently reported that intracerebroventricular (i.c.v.) injection of RTX inhibits the analgesic effect of acetaminophen in mice, suggesting supraspinal-selective TRPV1 desensitization19. In this manuscript, we present the precise protocol for i.c.v. injection and subsequent pain tests.
Direct injection of drugs into the ventricles of the brain makes it possible to study their central effects while minimalizing any peripheral effects. The i.c.v. injection procedure presented here is a modification of the method reported by Haley and McCormick20. This method is&#160;simple involving insertion of an injection needle into the lateral ventricles through the coronal suture and does not require any special equipment or surgical procedures for cannulation.
Peripheral local application of TRPV1 agonists evokes a burning pain sensation and neurogenic inflammation. Mice that are systemically treated with RTX, and TRPV1-KO mice, are insensitive to this stimulation13. We have performed intraplantar injection of RTX (RTX test) to confirm the preservation of peripheral TRPV1 in RTX-i.c.v. mice. This method is a modification of the conventional formalin test21.
It has been reported that mice systemically treated with RTX and TRPV1-KO mice show a normal threshold to mechanical stimuli11,13,22. Here we present a procedure for the tail pressure test for testing changes in the analgesic effect of acetaminophen.
All of these procedures are orthodox and versatile, and can be applied to studies of other drugs.

<table border="0" cellpadding="0" cellspacing="0" width="872">
	<tbody>
		<tr height="40">
			<td height="40" style="height:40px;width:247px;">Resiniferatoxin</td>
			<td style="width:191px;">LKT Laboratories</td>
			<td style="width:117px;">R1774</td>
			<td style="width:319px;">used for s.c./i.c.v. pretreatments and the RTX test</td>
		</tr>
		<tr height="20">
			<td height="20" style="height:20px;width:247px;">Acetaminophen</td>
			<td style="width:191px;">IWAKI SEIYAKU</td>
			<td style="width:117px;"></td>
			<td style="width:319px;">gifted from IWAKI SEIYAKU</td>
		</tr>
		<tr height="20">
			<td height="20" style="height:20px;width:247px;">Pentobarbital sodium salt</td>
			<td style="width:191px;">Tokyo Chemical Industry</td>
			<td style="width:117px;">P0776</td>
			<td style="width:319px;">used for anesthesia</td>
		</tr>
		<tr height="40">
			<td height="40" style="height:40px;width:247px;">Ethanol (99.5)</td>
			<td style="width:191px;">Wako Pure Chemical Industries</td>
			<td style="width:117px;">057-00456</td>
			<td style="width:319px;">used for dissolving RTX</td>
		</tr>
		<tr height="40">
			<td height="40" style="height:40px;width:247px;">Polyoxyethylene(20) Sorbitan Monooleate</td>
			<td style="width:191px;">Wako Pure Chemical Industries</td>
			<td style="width:117px;">161-21621</td>
			<td style="width:319px;">used for dissolving RTX</td>
		</tr>
		<tr height="20">
			<td height="20" style="height:20px;width:247px;">25 mL microsyringe</td>
			<td style="width:191px;">Hamilton</td>
			<td style="width:117px;">1702LT</td>
			<td style="width:319px;">used for i.c.v. injection</td>
		</tr>
		<tr height="20">
			<td height="20" style="height:20px;width:247px;">100 mL microsyringe</td>
			<td style="width:191px;">Hamilton</td>
			<td style="width:117px;">1710LT</td>
			<td style="width:319px;">used for intraplantar injection</td>
		</tr>
		<tr height="20">
			<td height="20" style="height:20px;width:247px;">26-gauge disposable needle</td>
			<td style="width:191px;">TERUMO</td>
			<td style="width:117px;">NN-2613S</td>
			<td style="width:319px;">used for i.c.v. injection</td>
		</tr>
		<tr height="20">
			<td height="20" style="height:20px;width:247px;">30-gauge disposable needle</td>
			<td style="width:191px;">NIPRO</td>
			<td style="width:117px;">01134</td>
			<td style="width:319px;">used for intraplantar injection</td>
		</tr>
		<tr height="40">
			<td height="40" style="height:40px;width:247px;">Pressure meter</td>
			<td style="width:191px;">Ugo Basile</td>
			<td style="width:117px;">Analgesy-Meter Type 7200</td>
			<td style="width:319px;">used for tail pressure test</td>
		</tr>
	</tbody>
</table>

intracerebroventricular treatment with resiniferatoxin and pain tests in mice

The transient receptor potential vanilloid type 1 (TRPV1), a thermosensitive cation channel, is known to trigger pain in the peripheral nerves. In addition to its peripheral function, its involvement in brain functions has also been suggested. Resiniferatoxin (RTX), an ultrapotent TRPV1 agonist, has been known to induce long-term desensitization of TRPV1, and this desensitization has been an alternative approach for investigating the physiological relevance of TRPV1-expressing cells. Here we describe a protocol for intracerebroventricular (i.c.v.) treatment with RTX in mice. Procedures are described for testing nociception to peripheral TRPV1 stimulation (RTX test) and mechanical stimulation (tail pressure test) then follow. Although the nociceptive responses of mice that had been administered RTX i.c.v. were comparable to those of the control groups, RTX-i.c.v.-administered mice were insensitive to the analgesic effect of acetaminophen, suggesting that i.c.v. RTX treatment can induce supraspinal-selective TRPV1 desensitization. This mouse model can be used as a convenient experimental system for studying the role of TRPV1 in brain/supraspinal function. These techniques can also be applied to studies of the central actions of other drugs.

The i.c.v.-treated mice show no apparent abnormalities in their appearance, spontaneous activities, body weight19 and core body temperature (Vehicle-treated group, 38.4 &#177; 0.3 &#176;C, n = 6; RTX-treated group, 38.7 &#177; 0.2 &#176;C, n = 6).
Figure 2A-B show the responsiveness of s.c.- or i.c.v.-treated mice to the intraplantar injection of RTX. The lic...

Watch this Scientific Journal Video about Intracerebroventricular Treatment with Resiniferatoxin and Pain Tests in Mice at JoVE.com

Intracerebroventricular Treatment with Resiniferatoxin and Pain Tests in Mice

The transient receptor potential vanilloid type 1 (TRPV1) in the supraspinal region has been suggested to play some roles in the brain function. Described here is a protocol for intracerebroventricular injection of resiniferatoxin for supraspinal TRPV1 desensitization in mice. Procedures for some pain tests are also presented.

The transient receptor potential vanilloid type 1 (TRPV1), a thermosensitive cation channel, is known to trigger pain in the peripheral nerves. In ...

The overall goal of this pretreatment is to generate mice and that TRPV1 channels are desensitized at supraspinal regions. This method can help answer key questions in the neuropharmalogical field. The main advantage of this technique is that supraspinal selective TRPV1 desensitization can be induced by a quite simple way.To begin this procedure, anesthetize a mouse with pentobarbital sodium intraperitoneally and check for loss of righting reflex. For subcutaneous treatment, inject RTX at 20 micrograms per milliliter into the back of the neck at a volume of 0.1 milliliter per 10 grams body weight. For the control group, inject the vehicle in the same way.Pass a disposable 27 gauge needle through a metal tube to expose 3 to 3.5 millimeter tip of the needle. Then hold the squamosal bones of the mouse firmly with the fingers. Move the needle laterally on the scalp and find the sagittal suture as the needle tip is hooked on the suture.Move the tip about one millimeter to the right, then move the tip rostrally to find the coronal suture. Afterward, insert the needle slowly and vertically. Inject the RTX solution over 10 seconds and hold it for another 10 seconds afterward.Subsequently, withdraw the needle slowly and return the mouse to its home cage. One week after RTX injection, at least 60 minutes prior to the test, transfer the mouse to the testing room. At least 30 minutes prior to the test, place the mouse in a plexiglass cage in order to allow it to acclimate to the environment.Then 20 minutes before the test, administer acetaminophen at 300 milligrams per kilogram to the mouse intraperitoneally. Hold the mouse loosely in a small cloth bag and insert a 30 gauge needle into the heel of the right hind paw. Advance the needle subcutaneously to near the walking pad and inject 20 microliters of RTX solution at 0.05 micrograms per milliliter.Subsequently, measure the period of licking and biting behavior in the glabrous region of the affected paw in each five-minute block. One week after RTX injection, transfer the mouse to the testing room. Place the mouse in a plexiglass cage.Mark the spots at 1.5 and 2.5 centimeters from the base of the tail. Next, hold the mouse loosely in a small cloth bag and apply pressure to the spots with a blunt probe. Please note that cutoff pressure of 250 gram is imposed to avoid tissue damage.Determine the pressure required to elicit escape behavior and calculate the nociceptive threshold by averaging the pressure determined at the two spots. Repeat the procedures every 15 minutes. After obtaining the baseline, administer acetaminophen at 300 micrograms per kilogram to the mouse intraperitoneally, then repeat the tail pressure test every 15 minutes until it reaches 90 minutes.These two figures show the responsiveness of SC or ICV treated mice to the intraplantar injection of RTX. The licking and biting behavior of vehicle-treated mice was remarkable in the first 10 minutes. Although the SC pretreated mice did not show licking and biting behavior at all, the ICV pretreated mice normally responded to the plantar injection of RTX.Moreover, intraperitoneal administration of acetaminophen reduced the licking and biting behavior of vehicle ICV treated mice, but not in RTX ICV treated mice. This graph shows the analgesic effects of acetaminophen at 300 micrograms per kilogram in the tail pressure test. Acetaminophen reduced the nociceptive response of vehicle pretreated mice in both tests, but the analgesic effects of acetaminophen were inhibited in mice that were pretreated ICV with RTX.Once mastered, this ICV injection technique can be applied for other drugs. Don't forget that working with Resiniferatoxin can be extremely hazardous and make sure to use rubber gloves and glasses for protection when handling.

intracerebroventricular-treatment-with-resiniferatoxin-pain-tests

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Neuroscience

Measuring Spinal Presynaptic Inhibition in Mice By Dorsal Root Potential Recording In Vivo

Presynaptic inhibition is one of the most powerful inhibitory mechanisms in the spinal cord. The underlying physiological mechanism is a depolarization of primary afferent fibers mediated by GABAergic axo-axonal synapses (primary afferent depolarization). The strength of primary afferent depolarization can be measured by recording of volume-conducted potentials at the dorsal root (dorsal root potentials, DRP). Pathological changes of presynaptic inhibition are crucial in the abnormal central processing of certain pain conditions and in some disorders of motor hyperexcitability. Here, we describe a method of recording DRP in vivo in mice. The preparation of spinal cord dorsal roots in the anesthetized animal and the recording procedure using suction electrodes are explained. This method allows measuring GABAergic DRP and thereby estimating spinal presynaptic inhibition in the living mouse. In combination with transgenic mouse models, DRP recording may serve as a powerful tool to investigate disease-associated spinal pathophysiology. In vivo recording has several advantages compared to ex vivo isolated spinal cord preparations, e.g. the possibility of simultaneous recording or manipulation of supraspinal networks and induction of DRP by stimulation of peripheral nerves.

Measuring Spinal Presynaptic Inhibition in Mice By Dorsal Root Potential Recording In Vivo

GABAergic presynaptic inhibition is a powerful inhibitory mechanism in the spinal cord important for motor and sensory signal integration in spinal cord networks. Underlying primary afferent depolarization can be measured by recording of dorsal root potentials (DRP). Here we demonstrate a method of in vivo recording of DRP in mice.

Presynaptic inhibition is one of the most powerful inhibitory mechanisms in the spinal cord. The underlying physiological mechanism is a depolarization of ...

Intracerebroventricular Viral Injection of the Neonatal Mouse Brain for Persistent and Widespread Neuronal Transduction

With the pace of scientific advancement accelerating rapidly, new methods are needed for experimental neuroscience to quickly and easily manipulate gene expression in the mouse brain. Here we describe a technique first introduced by Passini and Wolfe for direct intracranial delivery of virally-encoded transgenes into the neonatal mouse brain. In its most basic form, the procedure requires only an ice bucket and a microliter syringe. However, the protocol can also be adapted for use with stereotaxic frames to improve consistency for researchers new to the technique. The method relies on the ability of adeno-associated virus (AAV) to move freely from the cerebral ventricles into the brain parenchyma while the ependymal lining is still immature during the first 12-24 hr after birth. Intraventricular injection of AAV at this age results in widespread transduction of neurons throughout the brain. Expression begins within days of injection and persists for the lifetime of the animal. Viral titer can be adjusted to control the density of transduced neurons, while co-expression of a fluorescent protein provides a vital label of transduced cells. With the rising availability of viral core facilities to provide both off-the-shelf, pre-packaged reagents and custom viral preparation, this approach offers a timely method for manipulating gene expression in the mouse brain that is fast, easy, and far less expensive than traditional germline engineering.

Here we demonstrate a technique for widespread neuronal transduction by intraventricular injection of adeno-associated virus into the neonatal mouse brain. This method provides a rapid and easy way to attain lifelong expression of virally-delivered transgenes.

With the pace of scientific advancement accelerating rapidly, new methods are needed for experimental neuroscience to quickly and easily manipulate gene ...

A Simple and Inexpensive Method for Determining Cold Sensitivity and Adaptation in Mice

Cold hypersensitivity is a serious clinical problem, affecting a broad subset of patients and causing significant decreases in quality of life. The cold plantar assay allows the objective and inexpensive assessment of cold sensitivity in mice, and can quantify both analgesia and hypersensitivity. Mice are acclimated on a glass plate, and a compressed dry ice pellet is held against the glass surface underneath the hindpaw. The latency to withdrawal from the cooling glass is used as a measure of cold sensitivity.
Cold sensation is also important for survival in regions with seasonal temperature shifts, and in order to maintain sensitivity animals must be able to adjust their thermal response thresholds to match the ambient temperature. The Cold Plantar Assay (CPA) also allows the study of adaptation to changes in ambient temperature by testing the cold sensitivity of mice at temperatures ranging from 30 &#176;C to 5 &#176;C. Mice are acclimated as described above, but the glass plate is cooled to the desired starting temperature using aluminum boxes (or aluminum foil packets) filled with hot water, wet ice, or dry ice. The temperature of the plate is measured at the center using a filament T-type thermocouple probe. Once the plate has reached the desired starting temperature, the animals are tested as described above.
This assay allows testing of mice at temperatures ranging from innocuous to noxious. The CPA yields unambiguous and consistent behavioral responses in uninjured mice and can be used to quantify both hypersensitivity and analgesia. This protocol describes how to use the CPA to measure cold hypersensitivity, analgesia, and adaptation in mice.

The Cold Plantar Assay (CPA) measures cold responsiveness between 30 &#176;C and 5 &#176;C, and can also measure cold adaptation. This protocol describes how to use the CPA to measure cold hypersensitivity, analgesia, and adaptation in mice.

Cold hypersensitivity is a serious clinical problem, affecting a broad subset of patients and causing significant decreases in quality of life.  The cold ...

Intracerebroventricular Injection of Amyloid-&#946; Peptides in Normal Mice to Acutely Induce Alzheimer-like Cognitive Deficits

Amyloid-&#946; (A&#946;) is a major pathological mediator of both familial and sporadic Alzheimer's disease (AD). In the brains of AD patients, progressive accumulation of A&#946; oligomers and plaques is observed. Such A&#946; abnormalities are believed to block long-term potentiation, impair synaptic function, and induce cognitive deficits. Clinical and experimental evidences have revealed that the acute increase of A&#946; levels in the brain allows development of Alzheimer-like phenotypes. Hence, a detailed protocol describing how to acutely generate an AD mouse model via the intracerebroventricular (ICV) injection of A&#946; is necessary in many cases. In this protocol, the steps of the experiment with an A&#946;-injected mouse are included, from the preparation of peptides to the testing of behavioral abnormalities. The process of preparing the tools and animal subjects before the injection, of injecting the A&#946; into the mouse brain via ICV injection, and of assessing the degree of cognitive impairment are easily explained throughout the protocol, with an emphasis on tips for effective ICV injection of A&#946;. By mimicking certain aspects of AD with a designated injection of A&#946;, researchers can bypass the aging process and focus on the downstream pathology of A&#946; abnormalities.

Intracerebroventricular Injection of Amyloid-&amp;#946; Peptides in Normal Mice to Acutely Induce Alzheimer-like Cognitive Deficits

The amyloid-&#946; (A&#946;)-injected animal model enables the administration of a defined quantity and species of A&#946; fragments and reduces individual differences within each study group. This protocol describes the intracerebroventricular (ICV) injection of A&#946; without stereotactic instruments, enabling the production of Alzheimer-like behavioral abnormalities in normal mice.

Amyloid-&#946; (A&#946;) is a major pathological mediator of both familial and sporadic Alzheimer's disease (AD). In the brains of AD patients, ...

Burn Injury-Induced Pain and Depression-Like Behavior in Mice

Scalding water is the most common cause of burn injury in both elderly and young populations. It is one of the major clinical challenges because of the high mortality and sequelae in low- and middle-income countries. Burns frequently induce intense spontaneous pain and persistent allodynia as well as life-threatening problem. More importantly, excessive pain is often accompanied by depression, which may significantly decrease the quality of life. This article shows how to develop an animal model for the study of burn-induced pain and depression-like behavior. After anesthesia, burn injury was induced by dipping one hind paw of the mouse into hot water (65 &#176;C &plusmn; 0.5 &#176;C) for 3 s. The von Frey test and automated gait analysis were performed every 2 days after burn injury. In addition, depression-like behavior was examined using the forced swimming test, and the rota-rod test was performed to differentiate the abnormal motor function after burn injury. The main purpose of this study is to describe the development of an animal model for the study of burn injury-induced pain and depression-like behavior in mice.

A transient scald injury (65 &#176;C &plusmn; 0.5 &#176;C, 3 s) of one hind paw decreases the threshold (g) to von Frey filament stimulation of the ipsilateral side and alters gait pattern. Besides, burn injury induces depression-like behavior in the forced swimming test.

Scalding water is the most common cause of burn injury in both elderly and young populations. It is one of the major clinical challenges because of the ...

Mechanical Conflict-Avoidance Assay to Measure Pain Behavior in Mice

Pain comprises of both sensory (nociceptive) and affective (unpleasant) dimensions. In preclinical models, pain has traditionally been assessed using reflexive tests that allow inferences regarding pain's nociceptive component but provide little information about the affective or motivational component of pain. Developing tests that capture these components of pain are therefore translationally important. Hence, researchers need to use non-reflexive behavioral assays to study pain perception at that level. Mechanical conflict-avoidance (MCA) is an established voluntary non-reflexive behavior assay, for studying motivational responses to a noxious mechanical stimulus in a 3 chamber paradigm. A change in a mouse's location preference, when faced with competing noxious stimuli, is used to infer the perceived unpleasantness of bright light versus tactile stimulation of the paws. This protocol outlines a modified version of the MCA assay which pain researchers can use to understand affective-motivational responses in a variety of mouse pain models. Though not specifically described here, our example MCA data use the intraplantar complete Freund's adjuvant (CFA), spared nerve injury (SNI), and a fracture/casting model as pain models to illustrate the MCA procedure.

The mechanical conflict-avoidance assay is used as a non-reflexive readout of pain sensitivity in mice which can be used to better understand affective-motivational responses in a variety of mouse pain models.

Pain comprises of both sensory (nociceptive) and affective (unpleasant) dimensions. In preclinical models, pain has traditionally been assessed using ...

Intracerebroventricular Delivery of Gut-Derived Microbial Metabolites in Freely Moving Mice

The impact of gut microbiota and their metabolites on host physiology and behavior has been extensively investigated in this decade. Numerous studies have revealed that gut microbiota-derived metabolites modulate brain-mediated physiological functions through intricate gut-brain pathways in the host. Short-chain fatty acids (SCFAs) are the major bacteria-derived metabolites produced during dietary fiber fermentation by the gut microbiome. Secreted SCFAs from the gut can act at multiple sites in the periphery, affecting the immune, endocrine, and neural responses due to the vast distribution of SCFAs receptors. Therefore, it is challenging to differentiate the central and peripheral effects of SCFAs through oral and intraperitoneal administration of SCFAs. This paper presents a video-based method to interrogate the functional role of SCFAs in the brain via a guide cannula in freely moving mice. The amount and type of SCFAs in the brain can be adjusted by controlling the infusion volume and rate. This method can provide scientists with a way to appreciate the role of gut-derived metabolites in the brain.

Gut-derived microbial metabolites have multifaceted effects leading to complex behavior in animals. We aim to provide a step-by-step method to delineate the effects of gut-derived microbial metabolites in the brain via intracerebroventricular delivery via a guide cannula.

The impact of gut microbiota and their metabolites on host physiology and behavior has been extensively investigated in this decade. Numerous studies have ...

A Novel Approach for Pain Assessment from Pain Body Diagrams

Quantifying Pain Location and Intensity with Multimodal Pain Body Diagrams

To quantify an individual&#39;s subjective pain severity, standardized pain rating scales such as the numeric rating scale (NRS), visual analog scale (VAS), or McGill pain questionnaire (MPQ) are commonly used to assess pain on a numerical scale. However, these scales are often biased and fail to capture the complexity of pain experiences. In contrast, clinical practice often requires patients to report areas of pain by drawing on a body diagram, which is an effective but qualitative tool. The method presented here extracts quantifiable metrics from pain body diagrams (PBDs) which are validated against the NRS, VAS, and MPQ pain scales. By using a novel pressure-hue transformation on a digital tablet, different drawing pressures applied with a digital stylus can be represented as different hues on a PBD. This produces a visually intuitive diagram of hues ranging from green to blue to red, representing mild to moderate to most painful regions, respectively. To quantify each PBD, novel pain metrics were defined: (1) PBD mean intensity, which equals the sum of each pixel&#39;s hue value divided by the number of colored pixels, (2) PBD coverage, which equals the number of colored pixels divided by the total number of pixels on the body, and (3) PBD sum intensity, which equals the sum of all pixels&#39; hue values. Using correlation and information theory analyses, these PBD metrics were shown to have high concordance with standardized pain metrics, including NRS, VAS and MPQ. In conclusion, PBDs can provide novel spatial and quantitative information that can be repeatedly measured and tracked over time to comprehensively characterize a participant&#39;s pain experience.

Author Spotlight: Quantifying Pain Experience &amp;#8211; An Illustrative Approach Using the Pain Body Diagram 

Current pain scales used to quantify pain severity, such as visual analog scales, fail to capture the complexity of subjective pain experiences. Pain body diagrams are qualitative but may be more informative. The goal of this method is to extract quantitative metrics from pain body diagrams using novel pressure-hue transformation.

To quantify an individual&#39;s subjective pain severity, standardized pain rating scales such as the numeric rating scale (NRS), visual analog scale ...

Performing Intracerebroventricular Injection in Mice Using a Free-Hand Approach

Free-Hand Intracerebroventricular Injections in Mice

The investigation of neuroendocrine systems often requires the delivery of drugs, viruses, or other experimental agents directly into the brains of mice. An intracerebroventricular (ICV) injection allows the widespread delivery of the experimental agent throughout the brain (particularly in the structures near the ventricles). Here, methods for making free-hand ICV injections in adult mice are described. By using visual and tactile landmarks on the heads of mice, injections into the lateral ventricles can be made rapidly and reliably. The injections are made with a glass syringe held in the experimenter&#39;s hand and placed at approximate distances from the landmarks. Thus, this technique does not require a stereotaxic frame. Furthermore, this technique requires only brief isoflurane anesthesia, which permits the subsequent assessment of mouse behavior and/or physiology in awake, freely behaving mice. Free-hand ICV injection is a powerful tool for the efficient delivery of experimental agents into the brains of living mice and can be combined with other techniques such as frequent blood sampling, neural circuit manipulation, or in vivo recording to investigate neuroendocrine processes.

Author Spotlight: Insights, Innovations, and Future Avenues in Reproductive Neurocontrol 

Here, a simple and rapid approach for performing intracerebroventricular injections in mice using a free-hand approach (that is, without a stereotaxic device) is described.

The investigation of neuroendocrine systems often requires the delivery of drugs, viruses, or other experimental agents directly into the brains of mice. ...