Extension of time until cardiac arrest after injection of a lethal dose of pentobarbital in the hibernating Syrian hamster.

The aim of the present study was to examine whether entry of peripherally injected drugs into the central nervous system is reduced during hibernation. When a lethal dose of pentobarbital was injected intraperitoneally, the time until cardiac arrest was significantly longer in hibernating hamsters than in active controls. The time difference was not a consequence of low body temperature or diminished circulation, because mimicking these parameters in artificial hypothermia did not prolong the time. In contrast, there was no difference in the time until cardiac arrest after intracerebroventricular injection of the anesthetic. These results indicate that entry of peripherally injected anesthetics into the central nervous system may be suppressed during hibernation.