Alterations in the noradrenaline-containing nerve terminals in the periventricular portion of the rat hypothalamus following administration of chlorpromazine.

Abstract

Noradrenaline terminals in the periventricular hypothalamic region of the rat were visualized electron microscopically using a KMnO4 fixation technique. Alterations of these terminals were examined following chronic treatment of chlorpromazine (CPZ; 20 mg/kg) for one month. In the control rats, noradrenaline terminals with a typical synaptic contact accounted for only 7% of the total number of noradrenaline terminals. After 12 days of daily administration of CPZ, noradrenaline terminals with typical synapses increased markedly to approximately 3.5 times over those seenL in the controls. In addition, these terminals with a synapse-like formation also increased up to 2.5 times the number in the controls 30 days after chronic injections of CPZ.On some occasions, daily administration of CPZ for over 20 days resulted in degenerative changes of the noradrenaline terminals which contained membranous structures.