In:
International Journal of Molecular Sciences, MDPI AG, Vol. 24, No. 4 ( 2023-02-15), p. 3926-
Abstract:
Mechanisms for the α-adrenoceptor-mediated positive inotropy in neonatal mouse ventricular myocardium were studied with isolated myocardial preparations. The phenylephrine-induced positive inotropy was suppressed by prazosin, nifedipine, and chelerythrine, a protein kinase C inhibitor, but not by SEA0400, a selective Na+/Ca2+ exchanger inhibitor. Phenylephrine increased the L-type Ca2+ channel current and prolonged the action potential duration, while the voltage-dependent K+ channel current was not influenced. In the presence of cromakalim, an ATP-sensitive K+ channel opener, the phenylephrine-induced prolongation of action potential duration, as well as the positive inotropy, were smaller than in the absence of cromakalim. These results suggest that the α-adrenoceptor-mediated positive inotropy is mediated by an increase in Ca2+ influx through the L-type Ca2+ channel, and the concomitant increase in action potential duration acts as an enhancing factor.
Type of Medium:
Online Resource
ISSN:
1422-0067
DOI:
10.3390/ijms24043926
Language:
English
Publisher:
MDPI AG
Publication Date:
2023
detail.hit.zdb_id:
2019364-6
SSG:
12
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