Sexually Diergic Hypothalamic-Pituitary-Adrenal Axis Responses to Selective and Non-Selective Muscarinic Antagonists Prior to Cholinergic Stimulation by Physostigmine in Rats.

Sexually Diergic Hypothalamic-Pituitary-Adrenal Axis Responses to Selective and Non-Selective Muscarinic Antagonists Prior to Cholinergic Stimulation by Physostigmine in Rats.
Brain Res Bull. 2017 Nov 06;:
Authors: Smail MA, Soles JL, Karwoski TE, Rubin RT, Rhodes ME
Abstract
Central cholinergic systems regulate the hypothalamic-pituitary-adrenal (HPA) axis differentially in males and females (sexual diergism). We previously investigated the role of muscarinic receptors in this regulation by administering physostigmine (PHYSO), an acetylcholinesterase inhibitor, to male and female rats pretreated with scopolamine (SCOP), a nonselective muscarinic antagonist. SCOP pretreatment enhanced adrenocorticotropic hormone (ACTH) and corticosterone (CORT) responses in both sexes; males had greater ACTH responses while females had greater CORT responses. In the present study, we further explored the role of muscarinic receptor subtypes in HPA axis regulation by administering PHYSO to male and female rats following SCOP or various doses of either the M1 or the M2 selective muscarinic receptor antagonists, pirenzepine (PIREN) or methoctramine (METHO), respectively. Blood sampling occurred before and at multiple times after PHYSO. ACTH and CORT were determined by highly specific immunoassays. PIREN+PHYSO resulted in sustained, dose-dependent increases in ACTH and CORT: ACTH responses were similar in both sexes, CORT responses were greater in female...

Source: Brain Research Bulletin - November 6, 2017 Category: Neurology Authors: Smail MA, Soles JL, Karwoski TE, Rubin RT, Rhodes ME Tags: Brain Res Bull Source Type: research