Effect of cyproheptadine on the electrical activity of the hypothalamic feeding centres

Abstract

Electrodes were stereotaxically implanted in the lateral hypothalamic ‘feeding centre’ and medial ‘satiety centre’ as well as in other hypothalamic and cerebralcortical regions in cats. Electrical activity of these regions was recorded electroencephalographically, before and following i.v. injections of Periactin given daily for 7 days, in starving animals. In addition, changes in the eating behaviour, daily food intake, body weight as well as the arteriovenous glucose difference (to provide an index of glucose utilization in the body) were observed. Periactin injections produced hunger behaviour, increased food intake and gain in body weight. The EEG activity of the feeding centre showed an increase both in frequency and in amplitude, and this generally coincided with a decrease of glucose utilization in the body, with rise of both arterial and venous glucose level. The EEG activity of the satiety centre did not show any change, possibly as it was already low due to starvation. Similarly, other hypothalamic and cortical areas did not show any changes in their activity. Periactin injections also produced occasional paroxysms of drowsiness with the appearance of high voltage slow waves in all the EEG records.