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.

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7.9K Views.  Musashino University. 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...