The effects of temperature on synaptic transmission in hippocampal tissue slices

Fully submerged rat hippocampal tissue slices were exposed to temperature changes, and the effects on CA1 pyramidal cell electrophysiology studied. Raising the temperature from 29 to 33 or 37 °C simultaneously increased the focal-excitatory postsynaptic potentials and decreased the population spikes. These changes were largely reversible for slices warmed to 33 °C, but not for slices warmed to 37 °C. During warming transiently increased excitatory transmission was observed; the degree of increased transmission was related to the rate of temperature rise. It is postulated that neuronal membrane hyperpolarization with warming is responsible for several of the effects seen.