β‐ADRENOCEPTORS IN CIRCULAR AND LONGITUDINAL MYOMETRIAL MEMBRANES AND IN LUNG MEMBRANES FROM DIOESTROUS AND POST‐PARTUM GUINEA‐PIGS

Gwynneth M. Handberg, Elizabeth A. Davis, Solveiga Hall, Peter Molenaar, Roger J. Summers, Jocelyn N. Pennefather

Research output: Contribution to journalArticleResearchpeer-review

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Abstract

1. We have examined the binding of (—)[125I]‐cyanopindolol ((—)[125I]‐CYP) to membranes prepared from uterus and lung of dioestrous and post‐partum (1–6 days) guinea‐pigs. 2. The densities of β‐adrenoceptor binding sites in circular and longitudinal myometrium from dioestrous animals were similar, and approximately one‐eighth of those in the lung. Ascorbate and ethylenediaminetetraacetic acid in the incubation medium did not affect binding. 3. The numbers and affinities of β‐adrenoceptor binding sites in both myometrial layers and in lung parenchyma from post‐partum animals were similar to those in corresponding tissues from dioestrous animals. 4. The distribution of β‐adrenoceptor binding sites in the post‐partum uterus was examined using receptor autoradiography. Binding to circular and longitudinal muscle layers and to the endometrium was inhibited by (—)‐propranolol (1 μmol/l), by the β2‐adrenoceptor selective antagonist ICI 118,551 (70 nmol/l), but not by the β1‐adrenoceptor selective antagonist CGP 20712A (100 nmol/l), indicating that the β‐adrenoceptor present was of the β2‐subtype. 5. The ability of isoprenaline to compete for (—)[125I]‐CYP binding sites in uterine membranes from post‐partum animals was approximately twice that in corresponding preparations from dioestrous animals. 6. Changes in the numbers or affinity of β2‐adrenoceptors cannot account for the marked and selective enhancement of the actions of sympathomimetic amines at β‐adrenoceptors previously observed in longitudinal myometrium taken from post‐partum guinea‐pigs. It is suggested that enhancement of later steps in the chain of events between β‐adrenoceptor occupancy and uterine relaxation, and/or a decrease in the contribution of α‐adrenoceptors to the net effect of the amine might provide alternative explanations.

Original languageEnglish
Pages (from-to)681-693
Number of pages13
JournalClinical and Experimental Pharmacology and Physiology
Volume15
Issue number9
DOIs
Publication statusPublished - 1 Jan 1988

Keywords

  • autoradiography
  • guinea‐pig
  • lung
  • pregnancy
  • radioligand binding
  • separated myometrial layers
  • uterus
  • β ‐adrenoceptors

Cite this

@article{d154bb35f432477ba97214ce12f1f5c1,
title = "β‐ADRENOCEPTORS IN CIRCULAR AND LONGITUDINAL MYOMETRIAL MEMBRANES AND IN LUNG MEMBRANES FROM DIOESTROUS AND POST‐PARTUM GUINEA‐PIGS",
abstract = "1. We have examined the binding of (—)[125I]‐cyanopindolol ((—)[125I]‐CYP) to membranes prepared from uterus and lung of dioestrous and post‐partum (1–6 days) guinea‐pigs. 2. The densities of β‐adrenoceptor binding sites in circular and longitudinal myometrium from dioestrous animals were similar, and approximately one‐eighth of those in the lung. Ascorbate and ethylenediaminetetraacetic acid in the incubation medium did not affect binding. 3. The numbers and affinities of β‐adrenoceptor binding sites in both myometrial layers and in lung parenchyma from post‐partum animals were similar to those in corresponding tissues from dioestrous animals. 4. The distribution of β‐adrenoceptor binding sites in the post‐partum uterus was examined using receptor autoradiography. Binding to circular and longitudinal muscle layers and to the endometrium was inhibited by (—)‐propranolol (1 μmol/l), by the β2‐adrenoceptor selective antagonist ICI 118,551 (70 nmol/l), but not by the β1‐adrenoceptor selective antagonist CGP 20712A (100 nmol/l), indicating that the β‐adrenoceptor present was of the β2‐subtype. 5. The ability of isoprenaline to compete for (—)[125I]‐CYP binding sites in uterine membranes from post‐partum animals was approximately twice that in corresponding preparations from dioestrous animals. 6. Changes in the numbers or affinity of β2‐adrenoceptors cannot account for the marked and selective enhancement of the actions of sympathomimetic amines at β‐adrenoceptors previously observed in longitudinal myometrium taken from post‐partum guinea‐pigs. It is suggested that enhancement of later steps in the chain of events between β‐adrenoceptor occupancy and uterine relaxation, and/or a decrease in the contribution of α‐adrenoceptors to the net effect of the amine might provide alternative explanations.",
keywords = "autoradiography, guinea‐pig, lung, pregnancy, radioligand binding, separated myometrial layers, uterus, β ‐adrenoceptors",
author = "Handberg, {Gwynneth M.} and Davis, {Elizabeth A.} and Solveiga Hall and Peter Molenaar and Summers, {Roger J.} and Pennefather, {Jocelyn N.}",
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β‐ADRENOCEPTORS IN CIRCULAR AND LONGITUDINAL MYOMETRIAL MEMBRANES AND IN LUNG MEMBRANES FROM DIOESTROUS AND POST‐PARTUM GUINEA‐PIGS. / Handberg, Gwynneth M.; Davis, Elizabeth A.; Hall, Solveiga; Molenaar, Peter; Summers, Roger J.; Pennefather, Jocelyn N.

In: Clinical and Experimental Pharmacology and Physiology, Vol. 15, No. 9, 01.01.1988, p. 681-693.

Research output: Contribution to journalArticleResearchpeer-review

TY - JOUR

T1 - β‐ADRENOCEPTORS IN CIRCULAR AND LONGITUDINAL MYOMETRIAL MEMBRANES AND IN LUNG MEMBRANES FROM DIOESTROUS AND POST‐PARTUM GUINEA‐PIGS

AU - Handberg, Gwynneth M.

AU - Davis, Elizabeth A.

AU - Hall, Solveiga

AU - Molenaar, Peter

AU - Summers, Roger J.

AU - Pennefather, Jocelyn N.

PY - 1988/1/1

Y1 - 1988/1/1

N2 - 1. We have examined the binding of (—)[125I]‐cyanopindolol ((—)[125I]‐CYP) to membranes prepared from uterus and lung of dioestrous and post‐partum (1–6 days) guinea‐pigs. 2. The densities of β‐adrenoceptor binding sites in circular and longitudinal myometrium from dioestrous animals were similar, and approximately one‐eighth of those in the lung. Ascorbate and ethylenediaminetetraacetic acid in the incubation medium did not affect binding. 3. The numbers and affinities of β‐adrenoceptor binding sites in both myometrial layers and in lung parenchyma from post‐partum animals were similar to those in corresponding tissues from dioestrous animals. 4. The distribution of β‐adrenoceptor binding sites in the post‐partum uterus was examined using receptor autoradiography. Binding to circular and longitudinal muscle layers and to the endometrium was inhibited by (—)‐propranolol (1 μmol/l), by the β2‐adrenoceptor selective antagonist ICI 118,551 (70 nmol/l), but not by the β1‐adrenoceptor selective antagonist CGP 20712A (100 nmol/l), indicating that the β‐adrenoceptor present was of the β2‐subtype. 5. The ability of isoprenaline to compete for (—)[125I]‐CYP binding sites in uterine membranes from post‐partum animals was approximately twice that in corresponding preparations from dioestrous animals. 6. Changes in the numbers or affinity of β2‐adrenoceptors cannot account for the marked and selective enhancement of the actions of sympathomimetic amines at β‐adrenoceptors previously observed in longitudinal myometrium taken from post‐partum guinea‐pigs. It is suggested that enhancement of later steps in the chain of events between β‐adrenoceptor occupancy and uterine relaxation, and/or a decrease in the contribution of α‐adrenoceptors to the net effect of the amine might provide alternative explanations.

AB - 1. We have examined the binding of (—)[125I]‐cyanopindolol ((—)[125I]‐CYP) to membranes prepared from uterus and lung of dioestrous and post‐partum (1–6 days) guinea‐pigs. 2. The densities of β‐adrenoceptor binding sites in circular and longitudinal myometrium from dioestrous animals were similar, and approximately one‐eighth of those in the lung. Ascorbate and ethylenediaminetetraacetic acid in the incubation medium did not affect binding. 3. The numbers and affinities of β‐adrenoceptor binding sites in both myometrial layers and in lung parenchyma from post‐partum animals were similar to those in corresponding tissues from dioestrous animals. 4. The distribution of β‐adrenoceptor binding sites in the post‐partum uterus was examined using receptor autoradiography. Binding to circular and longitudinal muscle layers and to the endometrium was inhibited by (—)‐propranolol (1 μmol/l), by the β2‐adrenoceptor selective antagonist ICI 118,551 (70 nmol/l), but not by the β1‐adrenoceptor selective antagonist CGP 20712A (100 nmol/l), indicating that the β‐adrenoceptor present was of the β2‐subtype. 5. The ability of isoprenaline to compete for (—)[125I]‐CYP binding sites in uterine membranes from post‐partum animals was approximately twice that in corresponding preparations from dioestrous animals. 6. Changes in the numbers or affinity of β2‐adrenoceptors cannot account for the marked and selective enhancement of the actions of sympathomimetic amines at β‐adrenoceptors previously observed in longitudinal myometrium taken from post‐partum guinea‐pigs. It is suggested that enhancement of later steps in the chain of events between β‐adrenoceptor occupancy and uterine relaxation, and/or a decrease in the contribution of α‐adrenoceptors to the net effect of the amine might provide alternative explanations.

KW - autoradiography

KW - guinea‐pig

KW - lung

KW - pregnancy

KW - radioligand binding

KW - separated myometrial layers

KW - uterus

KW - β ‐adrenoceptors

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U2 - 10.1111/j.1440-1681.1988.tb01128.x

DO - 10.1111/j.1440-1681.1988.tb01128.x

M3 - Article

VL - 15

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EP - 693

JO - Clinical and Experimental Pharmacology and Physiology

JF - Clinical and Experimental Pharmacology and Physiology

SN - 0305-1870

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