Effect of Vasopressin V1b Receptor Blockade on Activity of the Hypothalamic-Pituitary-Adrenal Axis in Old Monkeys with Depression-Like and Anxious Behavior Subjected to Stress or Injected with Vasopressin

Abstract

The effect of selective antagonist of the arginine vasopressin (AVP) V1b receptors on the secretion of ACTH and corticosteroids in response to insulin-induced hypoglycemia and injection of AVP is studied in old Macaca mulatta females with depression-like and anxious behavior. Intravenous antagonist in a dose of 1.1-1.7 μg/kg inhibits the increase of ACTH concentration, induced by hypoglycemia or injection of AVP. The degree of increase in the concentrations of hydrocortisone and dehydroepiandrosterone sulfate has not changed or increased. The effects of AVP antagonist prove that previously detected disorders in the reaction of the hypothalamic-pituitary-adrenal system in old Macaca mulatta with depression-like and anxious behavior could be caused by excessive activation of vasopressin V1b receptors on the pituitary corticotrophs, while the use of V1b receptor antagonists seems to be a promising method for prevention of these disorders.

Keywords: depression-like and anxious behavior; hypothalamic—pituitary—adrenal axis; old Macaca mulatta; stress; vasopressin V1b receptor antagonist.