Norepinephrine and 5–Hydroxytryptamine Contents of Hypothalami of Rats Treated with Harmidinehydrochloride

Abstract

Norepinephrine and 5-hydroxytryptamine (5HT) contents of hypothalamus of male albino rats treated with various doses of harmidine were estimated at various time intervals after administration of the drug. Animals treated with reserpine alone and with reserpine one hour before and after the administration of harmidine were also included. In each group, a set of 10 animals were sacrificed at 0 minute, 15 minutes, 30 minutes, l hour and 24 hours time intervals. Harmidine produced a significant rise in both norepinephrine and 5-HT contents of hypothalamus, but in a reserpine treated group there was a constant fall in amine content over 24 hours. The amine content of animals treated with harmidine one hour after administration of reserpine was significantly higher than that of the reserpine treated group at the corresponding time intervals. These findings showed that harmidine probably raised the level of these amines through inhibition of MAO. Reserpine administration one hour after harmidine could produce a fall in amine content probably because harmidine had already made the enzyme M A 0 inactive.