Name: assessing changes in volatile general anesthetic sensitivity of mice after local or systemic pharmacological intervention
Uploaded: 2013-10-16T21:00:00
Description: Watch this Scientific Journal Video about Assessing Changes in Volatile General Anesthetic Sensitivity of Mice after Local or Systemic Pharmacological Intervention at JoVE.com

This work was supported by R01 GM088156 and T32 HL007713-18. We would like to thank Bill Pennie and Michael Carman from the University of Pennsylvania Research Instrumentation Shop for their help in assembling our righting reflex apparatus.

All procedures involving animals outlined herein have been approved by the University of Pennsylvania&#39;s Institutional Animal Care and Use Committee.
1. Overview of the Testing Apparatus
<ol>
	<li>The testing apparatus consists of 24 clear acrylic cylindrical chambers 10 cm in length and 5 cm in diameter (total volume of 200 ml). This size is appropriate for a typical 25 g adult mouse. Chambers have ports at each end for gas inlet and outlet. The outlet end is removable so that animals ma...

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	<li>Meyer, H. H. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Zur+theorie+der+alkoholnarkose.+I.+Mittheilung.+Welche+Eigenschaft+der+An#228;sthetica+bedingt+ihre+narkotische+Wirkung?.">Zur theorie der alkoholnarkose. I. Mittheilung. Welche Eigenschaft der An#228;sthetica bedingt ihre narkotische Wirkung?.</a> Naunyn Schmiedebergs Arch. Exp. Pathol. Pharmakol. 42, 109-137 .</li><li>Overton, C. E. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=.">.</a> Studien &#252;ber die Narkose: Zugleich ein Beitrag zur allgemeinen Pharmakologie. , (1901).</li><li>Bignall, K. 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Neurosci. 9 (5), 370-386 (2008).</li><li>Smith, W. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Responses+of+laboratory+animals+to+some+injectable+anaesthetics.">Responses of laboratory animals to some injectable anaesthetics.</a> Lab. Anim. 27 (1), 30-39 (1993).</li><li>Schernthaner, A., Lendl, C., Busch, R., Henke, J. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Clinical+evaluation+of+three+medetomidine--midazolam--ketamine+combinations+for+neutering+of+ferrets+(Mustela+putorius+furo)].">Clinical evaluation of three medetomidine--midazolam--ketamine combinations for neutering of ferrets (Mustela putorius furo)].</a> Berliner und M&#252;nchener tier&#228;rztliche Wochenschrift. 121 (1-2), 1-10 (2008).</li><li>Mohammad, F. K., Zangana, I. K., Abdul-Latif, A. R. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Medetomidine+sedation+in+sheep.">Medetomidine sedation in sheep.</a> Zentralblatt f&#252;r Veterin&#228;rmedizin. Reihe A. 40 (5), 328-331 (1993).</li><li>Nicholls, E. A., Louie, G. L., Prokocimer, P. G., Maze, M. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Halothane+anesthetic+requirements+are+not+affected+by+aminophylline+treatment+in+rats+and+dogs.">Halothane anesthetic requirements are not affected by aminophylline treatment in rats and dogs.</a> Anesthesiology. 65 (6), 637-641 (1986).</li><li>Tung, A., Szafran, M. J., Bluhm, B., Mendelson, W. 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I., Saidman 2nd, ., J, L., Brandstater, B. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Temperature+dependence+of+halothane+and+cyclopropane+anesthesia+in+dogs:+correlation+with+some+theories+of+anesthetic+action.">Temperature dependence of halothane and cyclopropane anesthesia in dogs: correlation with some theories of anesthetic action.</a> Anesthesiology. 26 (6), 764-770 (1965).</li><li>Vitez, T. S., White, P. F., Eger, E. I. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=2nd+Effects+of+hypothermia+on+halothane+MAC+and+isoflurane+MAC+in+the+rat.">2nd Effects of hypothermia on halothane MAC and isoflurane MAC in the rat.</a> Anesthesiology. 41 (1), 80-81 (1974).</li><li>Antognini, J. F. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Hypothermia+eliminates+isoflurane+requirements+at+20+degrees+C.">Hypothermia eliminates isoflurane requirements at 20 degrees C.</a> Anesthesiology. 78 (6), 1152-1156 (1993).</li><li>McKenzie, J. D., 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=Effects+of+temperature+on+the+anaesthetic+potency+of+halothane,+enflurane+and+ethanol+in+Daphnia+magna+(Cladocera:+Crustacea).">Effects of temperature on the anaesthetic potency of halothane, enflurane and ethanol in Daphnia magna (Cladocera: Crustacea).</a> Comp. Biochem. Physiol. C. 101 (1), 15-19 (1992).</li><li>Icaza, E. E., 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=Isoflurane-Induced+Changes+in+Righting+Response+and+Breathing+are+Modulated+by+RGS+Proteins.">Isoflurane-Induced Changes in Righting Response and Breathing are Modulated by RGS Proteins.</a> Anesth. Analg. 109 (5), 1500-1505 (2009).</li><li>Drexler, B., Antkowiak, B., Engin, E., Rudolph, U. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Identification+and+characterization+of+anesthetic+targets+by+mouse+molecular+genetics+approaches.">Identification and characterization of anesthetic targets by mouse molecular genetics approaches.</a> Can. 2 (2), 178-190 (2011).</li><li>Wafford, K. 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I. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Naturally+Occurring+Variability+in+Anesthetic+Potency+Among+Inbred+Mouse+Strains.">Naturally Occurring Variability in Anesthetic Potency Among Inbred Mouse Strains.</a> Anesth. 91 (3), 720-726 (2000).</li><li>Sun, Y., 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=High+throughput+modular+chambers+for+rapid+evaluation+of+anesthetic+sensitivity.">High throughput modular chambers for rapid evaluation of anesthetic sensitivity.</a> BMC Anesthesiol. 6 (1), 13 (2006).</li><li>Hu, F. Y., 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=Hypnotic+Hypersensitivity+to+Volatile+Anesthetics+and+Dexmedetomidine+in+Dopamine+&#946;-Hydroxylase+Knockout+Mice.">Hypnotic Hypersensitivity to Volatile Anesthetics and Dexmedetomidine in Dopamine &#946;-Hydroxylase Knockout Mice.</a> Anesthesiology. , (2012).</li><li>Kelz, M. B., 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=An+essential+role+for+orexins+in+emergence+from+general+anesthesia.">An essential role for orexins in emergence from general anesthesia.</a> Proc. Natl. Acad. Sci. U.S.A. 105 (4), 1309-1314 (2008).</li><li>Moore, J. 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L., McGinty, D. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Sleep-waking+discharge+patterns+of+ventrolateral+preoptic/anterior+hypothalamic+neurons+in+rats.">Sleep-waking discharge patterns of ventrolateral preoptic/anterior hypothalamic neurons in rats.</a> Brain Res. (1-2), 178-188 (1998).</li><li>Nelson, L. E., 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+sedative+component+of+anesthesia+is+mediated+by+GABAA+receptors+in+an+endogenous+sleep+pathway.">The sedative component of anesthesia is mediated by GABAA receptors in an endogenous sleep pathway.</a> Nat. Neurosci. 5 (10), 979-984 (2002).</li><li>Li, K. Y., Guan, Y., Krnjevi&#263;, K., Ye, J. 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Though assessment of LORR in a single mouse is a seemingly straightforward task, it is nevertheless essential to maintain identical physiological conditions between subjects in order to collect reliable data from a group of animals. The tightly regulated, high-capacity LORR apparatus presented here offers a way to standardize experiments and maximize efficiency. By following the basic tenets of thermoregulation and equal flow distribution, this system can be easily recreated and customized to fit individual experimenters...

General anesthetics are defined by their ability to cause a reversible state of hypnosis in a wide variety of species, yet an explanation as to how such a diverse class of drugs can all elicit a singular endpoint remains elusive. A number of theories have been posited over the years, starting with the Meyer-Overton correlation between anesthetic potency and lipid solubility, which suggested general membrane disruptions as the basis for hypnosis1,2. More recent evidence suggests that protein targets affecting neuronal signaling contribute to anesthetic effects. Mice have proven to be an indispensable model for exploring these theories because of the homology between murine and human anesthetic responsiveness. Though a mouse cannot be asked about its subjective awareness under general anesthesia, certain primitive reflexes serve as useful surrogate measures of rodent hypnosis. In the first few days following birth, mice develop a reflexive righting response that prevents them from being passively placed in a supine position3. The dose of anesthesia at which a mouse loses its righting reflex correlates well with human hypnotic doses4.
Assessment of loss of righting reflex (LORR) has become a widely used laboratory standard for testing anesthetic sensitivity in mice as well as a variety of other species including rat, guinea pig, rabbit, ferret, sheep, and dog5-8. The dose of a given anesthetic at which LORR will occur for members of a species is extremely consistent, but it can be shifted significantly by environmental factors. For example, sleep-deprived rats are more sensitive to both volatile and intravenous anesthetics9&#160;and rats with high aerobic capacity are less sensitive to isoflurane10. Hypothermia has also been shown to decrease the dose of numerous anesthetics required for hypnosis in a large spectrum of species11-14. In order to reliably identify the anesthetic dose at which LORR occurs in a group of experimental animals, it is critical that the assessment environment be carefully controlled to minimize stress, maintain euthermia, and deliver equal amounts of drug to all subjects. Not surprisingly, genetic factors are also known to alter anesthetic sensitivity15-18. Consequently, careful consideration should also be given to controlling for genetic background19.
We have developed an apparatus that ensures identical gaseous anesthetic delivery to each of 24 mice while maintaining a constant 37&#160;oC environment. The transparent cylindrical design of our exposure chambers allows for fast LORR assessment and easy integration of telemetric physiological measurements. This system has been shown to accurately measure isoflurane, halothane, and sevoflurane induction EC50 and time to emergence in wild-type mice20. We have also used this system to observe changes in anesthetic sensitivity in mice with genetic mutations and targeted hypothalamic lesions21-23. Here we describe two ways in which anesthetic sensitivity may be assessed after a pharmacological intervention using our controlled environment apparatus. Steady-state phenotyping of volatile anesthetic induction and emergence sensitivity requires 8-10 hours and is consequently best tailored for studies in which experimental conditions do not change, such as in chronic or long-acting pharmacological interventions. However, for short-acting treatments whose effects dissipate significantly over time we also present a simple procedure to evaluate changes in righting reflex following stereotactically-targeted microinjections or intravenous drug treatments that significantly impact anesthetic emergence. These tests represent a small subset of the potential applications for this controlled environment system, which could be adapted for any number of subjects of a variety of species to receive any type of inhaled therapeutic.

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			<td height="42" style="height:42px;width:115px;">Name of the Reagent</td>
			<td style="width:88px;">Company</td>
			<td style="width:88px;">Catalogue Number</td>
			<td style="width:171px;">Comments</td>
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			<td height="21" style="height:21px;width:115px;">Oxygen</td>
			<td style="width:88px;">Airgas</td>
			<td style="width:88px;">OX300</td>
			<td style="width:171px;"></td>
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			<td height="42" style="height:42px;width:115px;">Isoflurane</td>
			<td style="width:88px;">Butler Schein</td>
			<td style="width:88px;"></td>
			<td style="width:171px;">Any volatile anesthetic of interest may be substituted</td>
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			<td></td>
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			<td height="42" style="height:42px;width:115px;">Name of Material</td>
			<td style="width:88px;">Company</td>
			<td style="width:88px;">Catalogue Number</td>
			<td style="width:171px;">Comments</td>
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			<td height="42" style="height:42px;width:115px;">Mass flow meter- 10 SLPM</td>
			<td style="width:88px;">Omega Engineering</td>
			<td style="width:88px;">FMA-A2309</td>
			<td style="width:171px;"></td>
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			<td height="42" style="height:42px;width:115px;">Mass flow meter- 500 SCCM</td>
			<td style="width:88px;">Omega Engineering</td>
			<td style="width:88px;">FMA-A2305</td>
			<td style="width:171px;"></td>
		</tr>
		<tr height="63">
			<td height="63" style="height:63px;width:115px;">Anesthetic agent analyzer/gas indicator</td>
			<td style="width:88px;">AM Bickford</td>
			<td style="width:88px;">FI-21 Riken</td>
			<td style="width:171px;"></td>
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			<td height="42" style="height:42px;width:115px;">Heating water pump</td>
			<td style="width:88px;">Fisher Scientific</td>
			<td style="width:88px;">13-874-175</td>
			<td style="width:171px;"></td>
		</tr>
		<tr height="42">
			<td height="42" style="height:42px;width:115px;">Temperature transponders</td>
			<td style="width:88px;">BMDS</td>
			<td style="width:88px;">IPTT-300</td>
			<td style="width:171px;"></td>
		</tr>
		<tr height="42">
			<td height="42" style="height:42px;width:115px;">RF temperature reader</td>
			<td style="width:88px;">BMDS</td>
			<td style="width:88px;">DAS-6007</td>
			<td style="width:171px;"></td>
		</tr>
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assessing changes in volatile general anesthetic sensitivity of mice after local or systemic pharmacological intervention

One desirable endpoint of general anesthesia is the state of unconsciousness, also known as hypnosis. Defining the hypnotic state in animals is less straightforward than it is in human patients. A widely used behavioral surrogate for hypnosis in rodents is the loss of righting reflex (LORR), or the point at which the animal no longer responds to their innate instinct to avoid the vulnerability of dorsal recumbency. We have developed a system to assess LORR in 24 mice simultaneously while carefully controlling for potential confounds, including temperature fluctuations and varying gas flows. These chambers permit reliable assessment of anesthetic sensitivity as measured by latency to return of the righting reflex (RORR) following a fixed anesthetic exposure. Alternatively, using stepwise increases (or decreases) in anesthetic concentration, the chambers also enable determination of a population's sensitivity to induction (or emergence) as measured by EC50 and Hill slope. Finally, the controlled environmental chambers described here can be adapted for a variety of alternative uses, including inhaled delivery of other drugs, toxicology studies, and simultaneous real-time monitoring of vital signs.

Figure 1 demonstrates the utility of the step-wise LORR assay for determining long-term effects of a pharmacological intervention. Ibotenic acid (IBA) is an agonist of the glutamatergic N-methyl-D-asparate (NMDA) receptor that is often used as an excitotoxin to cause permanent neuronal lesions. Here we injected 10 nl of 1% IBA bilaterally into the ventrolateral preoptic area (VLPO) of C57BL/6J mice one week prior to testing. The majority of neurons in this nucleus exhibit low rates of firing during wakef...

Watch this Scientific Journal Video about Assessing Changes in Volatile General Anesthetic Sensitivity of Mice after Local or Systemic Pharmacological Intervention at JoVE.com

Assessing Changes in Volatile General Anesthetic Sensitivity of Mice after Local or Systemic Pharmacological Intervention

Loss of the righting reflex has long served as a standard behavioral surrogate for unconsciousness, also called hypnosis, in laboratory animals. Alterations in volatile anesthetic sensitivity caused by pharmacological interventions can be detected with a carefully controlled high-throughput assessment system, which may be adapted for delivery of any inhaled therapeutic.

One desirable endpoint of general anesthesia is  the state of unconsciousness, also known as hypnosis. Defining the hypnotic state in animals is  less ...

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Unit 1

Local Anesthetics

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Assessing Teratogenic Changes in a Zebrafish Model of Fetal Alcohol Exposure

Fetal alcohol syndrome (FAS) is a severe manifestation of embryonic exposure to ethanol. It presents with characteristic defects to the face and organs, ...

Monitoring of Systemic and Hepatic Hemodynamic Parameters in Mice

The use of mouse models in experimental research is of enormous importance for the study of hepatic physiology and pathophysiological disturbances. ...

The bm12 Inducible Model of Systemic Lupus Erythematosus (SLE) in C57BL/6 Mice

The bm12 Inducible Model of Systemic Lupus Erythematosus SLE in C57BL/6 Mice

Systemic lupus erythematosus (SLE) is an autoimmune disease with diverse clinical and immunological manifestations. Several spontaneous and inducible ...

Visualization of Vascular and Parenchymal Regeneration after 70% Partial Hepatectomy in Normal Mice

A modified silicone injection procedure was used for visualization of the hepatic vascular tree. This procedure consisted of in-vivo injection of the ...

Intrasplenic Transplantation of Hepatocytes After Partial Hepatectomy in NOD.SCID Mice

Partial hepatectomy is a versatile and reproducible method to study liver regeneration and the effect of cell based therapeutics in various pathological ...

Assessing Whole-Body Lipid-Handling Capacity in Mice

Assessing lipid metabolism is a cornerstone of evaluating metabolic function, and it is considered essential for in vivo metabolism studies. Lipids are a ...

Isolation of Regenerating Hepatocytes after Partial Hepatectomy in Mice

Partial hepatectomy has been widely used to investigate liver regeneration in mice, but the isolation of high yields of viable hepatocytes for downstream ...

Salidroside's Mechanism in Suppressing MCF-7 Cell Migration and Proliferation

Exploring the Pharmacological Action and Molecular Mechanism of Salidroside in Inhibiting MCF-7 Cell Proliferation and Migration

Exploring Salidroside's Molecular Mechanisms in Breast Cancer Treatment (Video) | JoVE

Salidroside (Sal) contains anti-carcinogenic, anti-hypoxic, and anti-inflammatory pharmacological activities. However, its underlying anti-breast cancer ...

Developing an Exercise Program for Rheumatoid Arthritis Patients

Evaluation of Changes in Hydration and Body Cell Mass with Bioelectrical Impedance Analysis after Exercise Program for Rheumatoid Arthritis Patients

Implementation of BIVA for Analyzing Disease Risk Factors in Patients with Low Body Cell Mass (Video) | JoVE

Rheumatoid arthritis (RA) is a debilitating disease that can result in complications such as rheumatoid cachexia. While physical exercise has shown ...

Anesthetic Thoracoscopy for Diagnosis of Pleural Effusions

Local Anesthetic Thoracoscopy for Undiagnosed Pleural Effusion

Local anesthetic thoracoscopy (LAT) is a minimally invasive diagnostic procedure gaining recognition among chest physicians for managing undiagnosed ...