Hypothermia induced in mice by intracerebroventricular injection of tryptamine: involvement of the 5-HT1 receptor.

The effect on the body temperature of mice of tryptamine administered by intracerebroventricular (i.c.v.) injection was studied. Tryptamine given i.c.v. produced a significant hypothermia above a dosage of 5 nmol. The hypothermic effect of tryptamine was inhibited by methysergide whereas ketanserin and p-chlorophenylalanine did not affect it. These data demonstrate that the hypothermia induced by tryptamine i.c.v. is produced by direct activation of the 5-HT1 receptor.