CENTRAL EFFECT OF 5-HYDROXYTRYPTAMINE, GAMMA-AMINO-BUTYRIC ACID AND CARBACHOL ON THERMOREGULATION IN NEONATAL GUINEA-PIG

  • 1 January 1976
    • journal article
    • research article
    • Vol. 47  (1) , 15-27
Abstract
5-Hydroxytryptamine [5-HT] (10 .mu.g), .gamma.-aminobutyric acid (20 .mu.g) and carbachol (1 .mu.g) were injected through the soft skull into the lateral cerebral ventricle of guinea pigs aged 2-12 days, at the slightly subneutral ambient temperatures of 30.degree. C. 5-HT produced no immediate change in O2 consumption, whereas colonic temperature fell rapidly. One hour after injecting 5-HT, when colonic temperature had decreased by about 0.5.degree. C, O2 consumption increased and after a lag of 30-40 min was followed by an increase in colonic temperature. .gamma.-aminobutyric acid (GABA) increased O2 consumption and colonic temperature after a latency of 30-60 min. Carbachol was followed by an immediate decrease in colonic temperature and O2 consumption. Colonic temperature was below the pre-injection level throughout the 5 h period of observation.