Action of angiotensin II on the electrical and mechanical activity of rat uterine smooth muscle

The effects of angiotensin II (A II) were studied on membrane potentials, ionic currents and isometric contractions in uterine smooth muscle strips from pregnant rats. In reference solution, A II in a low concentration (5 x 10-9M) exerted no effect on the resting potential or the action potential am...

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Autores principales: Sabato, U.C., Novas, M.L., Lowenstein, P., Zieher, L.M., De Roberts, E.
Formato: JOUR
Materias:
angiotensin
animal experiment
drug response
female genital system
in vitro study
myometrium
pregnancy
rat
smooth muscle contractility
smooth muscle fiber membrane potential
Acceso en línea:http://hdl.handle.net/20.500.12110/paper_00142999_v68_n3_p275_Sabato
Aporte de:
Biblioteca Digital - Facultad de Ciencias Exactas y Naturales (UBA) de Universidad de Buenos Aires
id todo:paper_00142999_v68_n3_p275_Sabato
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spelling todo:paper_00142999_v68_n3_p275_Sabato2023-10-03T14:12:10Z Action of angiotensin II on the electrical and mechanical activity of rat uterine smooth muscle Sabato, U.C. Novas, M.L. Lowenstein, P. Zieher, L.M. De Roberts, E. angiotensin animal experiment drug response female genital system in vitro study myometrium pregnancy rat smooth muscle contractility smooth muscle fiber membrane potential The effects of angiotensin II (A II) were studied on membrane potentials, ionic currents and isometric contractions in uterine smooth muscle strips from pregnant rats. In reference solution, A II in a low concentration (5 x 10-9M) exerted no effect on the resting potential or the action potential amplitude but significantly increased the rate of repetitive firing. However, in tetraethylammonium chloride (TEA)-containing solution, an increase in the action potential amplitude was always observed. The inward and outward currents were increased simultaneously, so that it was necessary to block the outward current with TEA ions in order to measure the enhancement of the inward current. The reduction of the deactivation time constants of the outward current as well as the increase in the inward current intensity could account for the acceleration of rhythmic activity in the presence of the peptide. The mechanical response to A II consisted of early tetanus which was followed by increased twitch contractions. The calcium contractures were also increased in depolarized strips. The tetanus could be dependent on the increase in and prolongation of repetitive firing while the enhancement of twitch contractions and calcium contractures could be explained by the increase in inward current intensity. JOUR info:eu-repo/semantics/openAccess http://creativecommons.org/licenses/by/2.5/ar http://hdl.handle.net/20.500.12110/paper_00142999_v68_n3_p275_Sabato
institution Universidad de Buenos Aires
institution_str I-28
repository_str R-134
collection Biblioteca Digital - Facultad de Ciencias Exactas y Naturales (UBA)
topic angiotensin
animal experiment
drug response
female genital system
in vitro study
myometrium
pregnancy
rat
smooth muscle contractility
smooth muscle fiber membrane potential
spellingShingle angiotensin
animal experiment
drug response
female genital system
in vitro study
myometrium
pregnancy
rat
smooth muscle contractility
smooth muscle fiber membrane potential
Sabato, U.C.
Novas, M.L.
Lowenstein, P.
Zieher, L.M.
De Roberts, E.
Action of angiotensin II on the electrical and mechanical activity of rat uterine smooth muscle
topic_facet angiotensin
animal experiment
drug response
female genital system
in vitro study
myometrium
pregnancy
rat
smooth muscle contractility
smooth muscle fiber membrane potential
description The effects of angiotensin II (A II) were studied on membrane potentials, ionic currents and isometric contractions in uterine smooth muscle strips from pregnant rats. In reference solution, A II in a low concentration (5 x 10-9M) exerted no effect on the resting potential or the action potential amplitude but significantly increased the rate of repetitive firing. However, in tetraethylammonium chloride (TEA)-containing solution, an increase in the action potential amplitude was always observed. The inward and outward currents were increased simultaneously, so that it was necessary to block the outward current with TEA ions in order to measure the enhancement of the inward current. The reduction of the deactivation time constants of the outward current as well as the increase in the inward current intensity could account for the acceleration of rhythmic activity in the presence of the peptide. The mechanical response to A II consisted of early tetanus which was followed by increased twitch contractions. The calcium contractures were also increased in depolarized strips. The tetanus could be dependent on the increase in and prolongation of repetitive firing while the enhancement of twitch contractions and calcium contractures could be explained by the increase in inward current intensity.
format JOUR
author Sabato, U.C.
Novas, M.L.
Lowenstein, P.
Zieher, L.M.
De Roberts, E.
author_facet Sabato, U.C.
Novas, M.L.
Lowenstein, P.
Zieher, L.M.
De Roberts, E.
author_sort Sabato, U.C.
title Action of angiotensin II on the electrical and mechanical activity of rat uterine smooth muscle
title_short Action of angiotensin II on the electrical and mechanical activity of rat uterine smooth muscle
title_full Action of angiotensin II on the electrical and mechanical activity of rat uterine smooth muscle
title_fullStr Action of angiotensin II on the electrical and mechanical activity of rat uterine smooth muscle
title_full_unstemmed Action of angiotensin II on the electrical and mechanical activity of rat uterine smooth muscle
title_sort action of angiotensin ii on the electrical and mechanical activity of rat uterine smooth muscle
url http://hdl.handle.net/20.500.12110/paper_00142999_v68_n3_p275_Sabato
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