cAMP concentration in the rat's preoptic region and cerebral cortex during sleep deprivation and recovery induced by ambient temperature.

cAMP concentrations in the preoptic region and cerebral cortex were studied in rats during exposure to low ambient temperature (-10 degrees C) and after return to control ambient temperature (22 degrees C). Significant changes in cAMP concentration were found only in the preoptic region. On prolonged exposure to low ambient temperature the nucleotide concentration decreased and the circadian rhythm, observed in control conditions, disappeared. Return to control ambient temperature after exposure to low ambient temperature induced a steep increase and a long-lasting plateau in cAMP concentration. The results are discussed in terms of interaction between thermoregulatory and sleep-wakefulness processes.