Effect of ondansetron and ICS 205-930 on radiation-induced hypothermia in rats.

This study determined the effects of the 5-hydroxytryptamine (5-HT) serotonin antagonists ondansetron and (3 alpha-tropanyl]-1H-indole-3-carboxylic acid ester HCl (ICS 205-930) on hypothermia induced in rats by irradiation and by administration of a 5-HT3 receptor agonist, 2-methyl-5-hydroxytryptamine (2-Me-5-HT). Intraperitoneal (i.p.) administration of 50-200 micrograms/kg of ondansetron and intraventricular administration of 5-20 micrograms of ondansetron attenuated hypothermia induced by 20 Gy gamma rays. However, the same doses of ondansetron administered i.p. or intraventricularly did not antagonize the hypothermia induced by 10 micrograms 2-Me-5-HT. In contrast, i.p. administration of 50-200 micrograms/kg of ICS 205-930 and intraventricular administration of 5-20 micrograms of ICS 205-930 attenuated hypothermia induced by radiation and 2-Me-5-HT. These results indicate that ICS 205-930 attenuates hypothermia induced by radiation and 2-Me-5-HT. However, the doses of ondansetron that attenuated radiation-induced hypothermia did not attenuate hypothermia induced by 2-Me-5-HT.