HYPOTHERMIA-INDUCED CHANGES OF AFFERENT SENSORY TRANSMISSION TO THE SI CORTEX OF RATS AND HAMSTERS

THE effects of acute lowering of body temperature on afferent sensory transmission to the primary somatosensory cortex were determined quant itatively in anaesthetized rats and hamsters. Rats showed no change in afferent sensory transmission until 27 degrees C, but dramatic suppre ssion between 26 degrees C and 22 degrees C, reaching 100% inhibition at 21 degrees C. Hamsters exhibited gradual suppression of sensory tra nsmission from 34 degrees C to 18 degrees C, reaching 95% inhibition a t 18 degrees C. Differential effects were also observed during rewarmi ng up to 37 degrees C. Response latencies were also differentially aff ected during hypothermia in rats and hamsters. These results suggest t he presence of inherently different neural mechanisms to process somat osensory information during transient lowering of body temperature bet ween hibernators and non-hibernators.