Peripheral and Central Muscarinic Cholinergic Receptors in Arterial Blood Pressure Regulation

Wray, David Walter, Peripheral and Central Muscarinic Cholinergic Receptors in Arterial Blood Pressure Regulation. Master of Science (Biomedical Sciences), December, 1999, 70 pp., 7 tables, 8 illustrations, references, 83 titles. This study was designed to test the hypothesis that an age-related vagal dysfunction compromises arterial blood pressure (ABP) regulation. Changes in heart rate (HR) and ABP during lower body negative pressure (LBNP) were compared between ten elderly (≥60 yrs) and ten young (≤30 yrs) adults. A separate, young group (n=10) was also assessed following muscarinic cholinergic (MC) blockade with atropine (central and peripheral receptor blockade) or glycopyrrolate (peripheral receptor blockade) to simulate vagal dysfunction. During the onset of LBNP -40 too, orthostatic hypotension (OH) was observed in both the older subjects and the post-blockade younger subjects, with a diminished HR response. Furthermore, the reflex response to hypertensive stimuli was augmented in the post-blockade younger subjects, also associated with a diminution in HR response. We concluded that age-related or pharmacologically stimulated vagal dysfunction compromises ABP regulation during hypotensive and hypertensive stimuli, and that the difference between atropine and glycopyrrolate was insignificant.