Meeting Abstract
Anesthetic drugs vary in their ability to induce and maintain anesthesia in animals due to variability in the form and function of the respiratory and cardiovascular systems. Because amphibians respire through their skin, immersion anesthetics have long been a standard method of anesthesia delivery for many species. However, because most amphibians are also capable of gas exchange through the buccopharyngeal cavity and lungs, we asked the question of whether all anesthetics were equally effective in amphibians that rely less on cutaneous gas exchange and more on bucco-pulmonary gas exchange. We compared the effects of injectable, inhalant, and immersion anesthetics in adult tiger salamanders (Ambystoma mavortium) in their ability to induce anesthesia. We administered anesthetics at several concentrations commonly used in research and veterinary medicine, and measured the effects on heart rate, respiratory rate and time to sedation, induction and recovery as compared to controls. We found that when compared to controls, none of the anesthetics affected heart rate, and all suppressed respiratory rate. Additionally, both injection and immersion anesthetics had cases of slow or no induction of anesthesia at low concentrations, but were effective at high concentrations. Immersion anesthetics had the highest variation in variables tested and had longer induction and recovery times when compared to injection anesthetics. We conclude that immersion, inhalant and injection anesthetics are all sufficient to induce anesthesia in terrestrial lunged salamanders, but that they are not all equal in their induction and recovery times or in their degree of variation. These results suggest that the method of anesthesia be evaluated in species prior to carrying out research with large samples.
