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Title: ( sup 3 H)rauwolscine binding to myometrial. alpha. sub 2 -adrenoceptors in pregnant guinea pig

Abstract

Uterine sympathetic nerves can exert an excitatory influence in late pregnancy and during parturition. Neuronal norepinephrine release is increased at these times and a diminished {alpha}{sub 2}-adrenoceptor-mediated prejunctional inhibition could account for this. To assess whether an altered receptor population may contribute, ({sup 3}H)rauwolscine was used to measure {alpha}{sub 2}-adrenoceptors in myometrial membranes at time intervals throughout pregnancy. High affinity ({sup 3}H)rauwolscine binding yielded linear Scatchard plots that in nonpregnant myometrium indicated a maximum binding density B{sub max} of 217 {plus minus} 42.4 fmol/mg protein. {alpha}{sub 2}-Adrenoceptor density was increased twofold at midpregnancy (31 days) and thereafter fell sharply by up to 90% toward term (67 {plus minus} 2 days). When uterine growth is accounted for and data are expressed in terms of total myometrial population, {alpha}{sub 2}-adrenoceptor number was eightfold (midpregnancy) and fourfold (term) greater than the nonpregnant value of 804 {plus minus} 322.4 fmol/uterus. {alpha}{sub 2}-Adrenoceptors were also found to bind dopamine with high affinity. These observations could indicate a pregnancy-related change in uterine sympathetic autoinhibitory capacity and, since {alpha}{sub 2}-adrenoceptors appear also to be located postjunctionally, explain in part reports of altered myometrial responsiveness to norepinephrine infusion and also the uterotonic actions of dopamine.

Authors:
;  [1]
  1. Univ. of Oxford (England)
Publication Date:
OSTI Identifier:
7191887
Resource Type:
Journal Article
Journal Name:
American Journal of Physiology; (USA)
Additional Journal Information:
Journal Volume: 255:3; Journal ID: ISSN 0002-9513
Country of Publication:
United States
Language:
English
Subject:
59 BASIC BIOLOGICAL SCIENCES; ANTIHYPERTENSIVE AGENTS; RADIORECEPTOR ASSAY; PREGNANCY; PHYSIOLOGY; UTERUS; ALKALOIDS; BIOCHEMICAL REACTION KINETICS; DOPAMINE; GUINEA PIGS; LIGANDS; RECEPTORS; SYMPATHOMIMETICS; TRITIUM COMPOUNDS; AMINES; ANIMALS; AROMATICS; AUTONOMIC NERVOUS SYSTEM AGENTS; BODY; CARDIOTONICS; CARDIOVASCULAR AGENTS; DRUGS; FEMALE GENITALS; HYDROGEN COMPOUNDS; HYDROXY COMPOUNDS; ISOTOPE APPLICATIONS; KINETICS; MAMMALS; MEMBRANE PROTEINS; NEUROREGULATORS; ORGANIC COMPOUNDS; ORGANS; PHENOLS; POLYPHENOLS; PROTEINS; REACTION KINETICS; RODENTS; TRACER TECHNIQUES; VERTEBRATES; 551001* - Physiological Systems- Tracer Techniques

Citation Formats

Arkinstall, S J, and Jones, C T. ( sup 3 H)rauwolscine binding to myometrial. alpha. sub 2 -adrenoceptors in pregnant guinea pig. United States: N. p., 1988. Web.
Arkinstall, S J, & Jones, C T. ( sup 3 H)rauwolscine binding to myometrial. alpha. sub 2 -adrenoceptors in pregnant guinea pig. United States.
Arkinstall, S J, and Jones, C T. 1988. "( sup 3 H)rauwolscine binding to myometrial. alpha. sub 2 -adrenoceptors in pregnant guinea pig". United States.
@article{osti_7191887,
title = {( sup 3 H)rauwolscine binding to myometrial. alpha. sub 2 -adrenoceptors in pregnant guinea pig},
author = {Arkinstall, S J and Jones, C T},
abstractNote = {Uterine sympathetic nerves can exert an excitatory influence in late pregnancy and during parturition. Neuronal norepinephrine release is increased at these times and a diminished {alpha}{sub 2}-adrenoceptor-mediated prejunctional inhibition could account for this. To assess whether an altered receptor population may contribute, ({sup 3}H)rauwolscine was used to measure {alpha}{sub 2}-adrenoceptors in myometrial membranes at time intervals throughout pregnancy. High affinity ({sup 3}H)rauwolscine binding yielded linear Scatchard plots that in nonpregnant myometrium indicated a maximum binding density B{sub max} of 217 {plus minus} 42.4 fmol/mg protein. {alpha}{sub 2}-Adrenoceptor density was increased twofold at midpregnancy (31 days) and thereafter fell sharply by up to 90% toward term (67 {plus minus} 2 days). When uterine growth is accounted for and data are expressed in terms of total myometrial population, {alpha}{sub 2}-adrenoceptor number was eightfold (midpregnancy) and fourfold (term) greater than the nonpregnant value of 804 {plus minus} 322.4 fmol/uterus. {alpha}{sub 2}-Adrenoceptors were also found to bind dopamine with high affinity. These observations could indicate a pregnancy-related change in uterine sympathetic autoinhibitory capacity and, since {alpha}{sub 2}-adrenoceptors appear also to be located postjunctionally, explain in part reports of altered myometrial responsiveness to norepinephrine infusion and also the uterotonic actions of dopamine.},
doi = {},
url = {https://www.osti.gov/biblio/7191887}, journal = {American Journal of Physiology; (USA)},
issn = {0002-9513},
number = ,
volume = 255:3,
place = {United States},
year = {Thu Sep 01 00:00:00 EDT 1988},
month = {Thu Sep 01 00:00:00 EDT 1988}
}