The central effect of 5-hydroxytryptamine, gamma-amino-butyric acid and carbachol on thermoregulation in the neonatal guinea pig.
5-Hydroxytryptamine (10 microgram), gamma-amino-butyric acid (20 microgram) and carbachol (1 microgram) were injected through the soft skull into the lateral cerebral ventricle of guinea pigs aged 2 to 12 days, at the slightly subneutral ambient temperature of 30 degrees C. 5-Hydroxytryptamine (5-HT) produced no immediate change in oxygen consumption, whereas colonic temperature fell rapidly. One hour after injecting 5-HT, when colonic temperature had decreased by about 0.5 degrees C, oxygen consumption increased and after a lag of 30--40 min was followed by an increase in colonic temperature. Gamma-amino-butyric acid (GABA) increased oxygen consumption and colonic temperature after a latency of 30--60 min. Carbachol was followed by an immediate decrease in colonic temperature and oxygen consumption. Colonic temperature was below the pre-injection level throughout the five-hour period of observation.
D000613:Aminobutyrates / Q000494:pharmacology*; D000818:Animals; D000831:Animals, Newborn; D001833:Body Temperature Regulation / Q000187:drug effects*; D002217:Carbachol / Q000008:administration & dosage / Q000494:pharmacology*; D006168:Guinea Pigs; D007276:Injections, Intraventricular; D010101:Oxygen Consumption / Q000187:drug effects; D012701:Serotonin / Q000008:administration & dosage / Q000494:pharmacology*; D013997:Time Factors; D005680:gamma-Aminobutyric Acid / Q000008:administration & dosage / Q000494:pharmacology*
D000613:Aminobutyrates; D012701:Serotonin; D005680:gamma-Aminobutyric Acid; D002217:Carbachol