Arousal from hibernation by intrahypothalamic injections of biogenic amines in ground squirrels.

BECKMAN, ALEXANDER, AND EVELYN SATINOFF. Arousal from hibernation by intrahypothalamic injections of biogenic amines in ground squirrels. Am. J. Physiol. 222(4) : 875-879. 1972.--Injections of low doses of norepinephrine or 5-hydroxytryptamine into the preoptic and anterior area of the hypothalamus in hibernating ground squirrels (Citellus lateralis) initiated complete arousal from hibernation. Nonamine control solutions did not initiate arousal nor did amine injections into extrahypothalamic sites. Records of hypothalamic temperature (Thy) taken during these amineinduced arousals were indistinguishable from those taken during %pontaneous” arousals or during arousals produced by sensory stimulation. Injection of these amines into the same region of the brain in nonhibernating ground squirrels led to increases in Thy of up to 2.2 c.