HIBERNATION-RELATED MODIFICATION OF ACTIVITY-DEPENDENT PROPERTIES OF SYNAPTIC TRANSMISSION IN HAMSTER HIPPOCAMPUS

In order to reveal hibernation-related modifications in the cold resis tance of neuronal function, we measured the temperature below which st imulus-evoked synaptic transmission was blocked (threshold temperature ) in area CA1 of hippocampal slices from warm-acclimated golden hamste rs, from hibernating golden hamsters, and from rats. The threshold tem peratures were separately analyzed for the first and the second respon se evoked by paired-pulse stimulation (pulse interval 50 ms). 1. In sl ices from golden hamsters the threshold temperatures for evoked synapt ic transmission were at about 17-degrees-C, which is 2 - 3-degrees-C h igher than in rat slices. This indicates that hippocampal function at lower temperatures than in nonhibernators is not a prerequisite for hi bernation. 2. In slices from hibernating hamsters, the threshold tempe rature for the second response in the paired-pulse stimulation was sig nificantly lower than in slices from warm-acclimated hamsters. For the first response, in contrast, the difference was not significant. This indicates a hibernation-related modification of activity-dependent ne uronal processes.