Quantitation of alpha 1-adrenergic receptors in porcine uterine and mesenteric arteries

Journal Article · Thu Nov 01 00:00:00 EST 1984 · Am. J. Obstet. Gynecol.; (United States)

DOI:https://doi.org/10.1016/S0002-9378(84)90425-3· OSTI ID:5983101

Farley, D B; Ford, S P; Reynolds, L P; Bhatnagar, R K; Van Orden, D E

The activation of vascular alpha-adrenergic receptors may be involved in the control of uterine blood flow. A radioligand binding assay with the use of the alpha 1-adrenergic antagonist /sup 3/H-WB-4101 was established to characterize the alpha-adrenergic receptors in uterine and mesenteric arterial membranes obtained from nonpregnant pigs. Specific binding of /sup 3/H-WB-4101 was rapid, saturable, and exhibited the alpha-adrenergic agonist potency order of (-)-epinephrine inhibition constant (Ki) . 0.6 mumol/L greater than (-)-norepinephrine (Ki . 1.5 mumol/L) much greater than (-)-isoproterenol (Ki . 120 mumol/L). The alpha-adrenergic antagonist phentolamine (Ki . 6.0 nmol/L) was 200 times more potent than the beta-adrenergic antagonist (+/-)-propranolol (Ki . 1,200 nmol/L); the alpha 1-selective antagonist prazosin (Ki . 1.2 nmol/L) was 130 times more potent than the alpha 2-selective antagonist yohimbine (Ki . 160 nmol/L). Scatchard analysis, as well as iterative curve-fitting analysis, demonstrated that /sup 3/H-WB-4101 binding by arterial membranes was to a single class of binding sites. Uterine arteries exhibited greater maximal binding capacity (BMax) than that of mesenteric arteries (47.5 +/- 3.2 versus 30.9 +/- 3.6 fmol per milligram of protein, p less than 0.01), but the uterine artery dissociation constant (Kd) was higher, thus indicating a lower affinity, when compared with mesenteric artery (0.43 +/- 0.04 versus 0.33 +/- 0.04 nmol/L, p less than 0.05).

• Research Organization: Univ. of Iowa, Iowa City
• OSTI ID: 5983101
• Journal Information: Am. J. Obstet. Gynecol.; (United States), Vol. 150:5
• Country of Publication: United States
• Language: English

Related Subjects

59 BASIC BIOLOGICAL SCIENCES
SYMPATHOMIMETICS
RECEPTORS
UTERUS
BLOOD FLOW
AFFINITY
ARTERIES
BIOCHEMISTRY
CELL MEMBRANES
CHEMICAL BONDS
COMPARATIVE EVALUATIONS
LIGANDS
SWINE
TRACER TECHNIQUES
TRITIUM COMPOUNDS
ANIMALS
AUTONOMIC NERVOUS SYSTEM AGENTS
BLOOD VESSELS
BODY
CARDIOVASCULAR SYSTEM
CELL CONSTITUENTS
CHEMISTRY
DOMESTIC ANIMALS
DRUGS
FEMALE GENITALS
ISOTOPE APPLICATIONS
LABELLED COMPOUNDS
MAMMALS
MEMBRANES
ORGANS
VERTEBRATES
550201* - Biochemistry- Tracer Techniques