Appendix: Basics of Anesthesia for Experimental Animals

Abstract

Every anesthetic agent will affect not only the nervous system but, to some extent, every organ’s physiology. If chronic preparation and awake animals cannot be utilized, an anesthetic for acute experiments must be selected which will not affect the objectives of the experimental protocol. Further, it must be kept in mind that restraint alone can have an adverse effect, and that under general anesthesia most laboratory animals are prone to develop hypothermia. Hypothermia potentiates the depressant effect of most anesthetics on the CNS; even with a light anesthesia, a broad spectrum of heat-loss compensatory mechanisms are activated. Reactive vasoconstriction, increase of peripheral vascular resistance, decrease in cardiac output, etc. can all affect cardiovascular experimentation and introduce artifacts of contrast media into the study. Thus, the importance of preventing hypothermia cannot be overstated. Monitoring of body temperature most conveniently with a rectal thermometer should be, like the use of heat pads, an integral part of the experimental setup.