Faculty Collaboration Database

Adrenal blood flow and secretory effects of adrenergic receptor stimulation. Am J Physiol 1994 Jan;266(1 Pt 2):H220-7

Date

01/01/1994

Pubmed ID

7905716

DOI

10.1152/ajpheart.1994.266.1.H220

Scopus ID

2-s2.0-0028088891   8 Citations

Abstract

To evaluate effects of adrenergic receptor stimulation on regional adrenal blood flow and secretion, pentobarbital-anesthetized dogs (n = 5-6/group) received the beta-agonist isoproterenol (group I), the alpha 1-agonist phenylephrine (group II), or the alpha 2-agonist dexmedetomidine (group III). Measurements of adrenal cortical (CQ) and medullary (MQ) blood flow (radiolabeled microspheres) and catecholamine secretion were made before and during agonist infusion. Isoproterenol increased catecholamine secretion but had no direct effect on MQ or CQ. In contrast, phenylephrine increased MQ and CQ four- and twofold, respectively. Dexmedetomidine had no effect on MQ or catecholamine secretion. To evaluate whether blood flow effects of phenylephrine were due to increases in mean arterial blood pressure (MAP) or related to activation of alpha 1-adrenergic receptors, two additional groups of animals received phenylephrine; group IV had MAP maintained at baseline by controlled hemorrhage into a pressurized bottle; group V received prazosin before phenylephrine. Prevention of MAP increase did not prevent the vasodilation response to phenylephrine, but it was completely blocked by prazosin. Canine adrenal homogenates incubated with the alpha 1-adrenoceptor ligand, 125I-labeled 2-[beta-(4-hydroxyphenyl)ethlaminomethyl]tetralone, demonstrated specific and saturable binding, supporting the presence of alpha 1-adrenergic receptors. We conclude that increases in MQ and CQ elicited by phenylephrine appear to be due to alpha 1-receptor stimulation. The mechanism responsible for this vasodilation is not known.

Author List

Ligier B, Breslow MJ, Clarkson K, Raff H, Traystman RJ

Author

Hershel Raff PhD Professor in the Medicine department at Medical College of Wisconsin

MESH terms used to index this publication - Major topics in bold

Adrenal Cortex
Adrenal Glands
Adrenal Medulla
Adrenergic Agonists
Animals
Autoradiography
Blood Pressure
Catecholamines
Dogs
Microspheres
Prazosin
Regional Blood Flow