Comparison of intracisternally and intraperitoneally injected harmaline on body temperature and tremor in the rat

Abstract

Low doses of harmaline (1–10 mg/kg) injected intraperitoneally into rats caused hypothermia, while higher doses (10–30 mg/kg) induced tremor in addition to hypothermia. Harmaline injected intracisternally decreased body temperature without inducing tremor. To induce a maximal fall in body temperature following intraperitoneal injection of harmaline, 1000 times more harmaline was needed than after intracisternal administration. Harmaline by this route induced hypothermia much faster than by intraperitoneal injection. It is concluded that harmaline-induced hypothermia is at least partly localized in the central nervous system and is not associated with the tremor.