Amygdalar injections of vasopressin and its antagonist do not disrupt the circadian rhythm of food and water intake in the rat.

ABSTRACT

There is an indication that areas of the brain other than the suprachiasmatic nuclei (SCN), the known neural circadian pacemaker, are involved in the control of circadian rhythms. The present study investigated the role of amygdala in the circadian rhythms of food and water intake. Vasopressin and its antagonist d(CH2)5Tyr(Me)AVP were injected into the amygdala bilaterally through chronically implanted stainless steel cannulae. The results of the study have shown that neither vasopressin nor its antagonist d(CH2)5Tyr(Me)AVP alters the circadian rhythm of food and water intake thereby showing that vasopressinergic neurons/projections to amygdala are not involved in the control of circadian rhythms of food and water intake and amygdala is not likely to be an additional oscillator.