Comparison of alpha-2 adrenergic receptors and their regulation in rodent and porcine species

Journal Article · Wed Feb 01 04:00:00 EST 1984 · J. Pharmacol. Exp. Ther.; (United States)

OSTI ID:6723759

Feller, D J; Bylund, D B

The alpha-2 adrenergic antagonist (/sup 3/H)yohimbine (YOH) and the alpha-2 agonist (/sup 3/H)p-aminoclonidine (PAC) saturably label high-affinity binding sites in the submandibular gland from 3-week-old rats and 5-week-old pigs and in the lung from neonatal rats and 5-week-old pigs. (/sup 3/H)YOH had KD values of 5.5, 1.8, 0.45 and 0.22 nM in the rat gland and lung and porcine gland and lung, respectively. KD values of 2.4, 5.3 and 1.3 nM were found for (/sup 3/H)PAC in rodent and pig submandibular gland and pig lung, respectively. Both /sup 3/H-ligands labeled approximately the same density of sites within each tissue except in the rat lung in which (/sup 3/H)PAC binding was too low to reliably estimate. In all cases the pharmacologic profile was indicative of an alpha-2 adrenergic receptor site. However, the Ki of yohimbine vs. (/sup 3/H)PAC was 30- to 140-fold higher for the rodent relative to the porcine species. GTP decreased the affinity of (-)-epinephrine and PAC at (/sup 3/H)YOH-labeled sites in the pig gland and lung, but did not shift the affinity of epinephrine in the rat gland. These results suggest the possibility of subtype or species differences for the alpha-2 receptor. The Ki values of the antagonists YOH and phentolamine were different at (/sup 3/H)PAC and (/sup 3/H)YOH sites. GTP caused a dose-dependent reduction in (/sup 3/H)PAC binding in the porcine submandibular gland and lung. At 10 microM GTP, this loss was due to a decrease in /sup 3/H-agonist affinity, but not density.

• Research Organization: Univ. of Missouri, Columbia
• OSTI ID: 6723759
• Journal Information: J. Pharmacol. Exp. Ther.; (United States), Journal Name: J. Pharmacol. Exp. Ther.; (United States) Vol. 228:2; ISSN JPETA
• Country of Publication: United States
• Language: English

Related Subjects

551001* -- Physiological Systems-- Tracer Techniques
59 BASIC BIOLOGICAL SCIENCES
ADRENAL HORMONES
ADRENALINE
ANIMALS
AUTONOMIC NERVOUS SYSTEM AGENTS
BODY
CARDIOTONICS
CARDIOVASCULAR AGENTS
DOMESTIC ANIMALS
DRUGS
GLANDS
HORMONES
ISOTOPE APPLICATIONS
LABELLED COMPOUNDS
LUNGS
MAMMALS
NEUROREGULATORS
ORGANS
PHYSIOLOGY
RATS
RECEPTORS
RESPIRATORY SYSTEM
RODENTS
SALIVARY GLANDS
STEROID HORMONES
SWINE
SYMPATHOMIMETICS
TRACER TECHNIQUES
TRITIUM COMPOUNDS
VERTEBRATES