当前位置： SCI文献检索 > EUROPEAN JOURNAL OF PHARMACOLOGY期刊下所有文献 > Effects of phorbol ester on carbachol-induced contraction in bovine ciliary muscle: possible involvement of protein kinase C.

Effects of phorbol ester on carbachol-induced contraction in bovine ciliary muscle: possible involvement of protein kinase C.

Abstract：

:The aim of the research was to characterize muscarinic receptors of bovine ciliary muscle and to investigate the desensitization process. The role of protein kinase C was analyzed. The results show that muscarinic receptors of bovine ciliary muscle have the pharmacological characteristics of the M3 subtype. Acute exposure to phorbol esters (1 microM phorbol 12,13-dibutyrate, PDB, or 0.1 microM phorbol 12-myristate 13-acetate, PMA, for 15 and 5 min, respectively) resulted in antagonism of muscarinic receptor-mediated contraction. Long-term pretreatment (18 h) with PMA to down-regulate protein kinase C resulted in potentiation of carbachol-induced contraction, reduction of agonist-induced desensitization and loss of phorbol ester-induced desensitization. Staurosporine (3 microM) and H7 [1-(5-isoquinolinesulfonyl)-2-methyl-piperazine] (1 microM), protein kinase C inhibitors, produced a significant potentiation of the contractile effect of carbachol, reduced the desensitization produced by repeated addition of carbachol and suppressed that induced by phorbol esters. In vitro incubation with carbachol, PDB or PMA did not cause any modification of the binding of labeled [3H]quinuclidinyl benzilate. In vitro incubation with PDB and PMA produced, as expected, a significant translocation of protein kinase C from the cytosol to the membrane. The incubation of the ciliary muscle with carbachol, using the protocol of exposure that induced maximal desensitization of contractile responses, produced a significant redistribution of the enzyme from the cytosol to the membrane. These findings suggest that agonist-induced modulation of functional cholinergic sensitivity in ciliary muscle is correlated, at least partially, to the translocation of protein kinase C from the cytosol to the membrane. The desensitization by phorbol esters is completely due to protein kinase C activation; during the desensitization process, direct modification of the density and affinity of muscarinic receptors is not involved.

journal_name

Eur J Pharmacol

journal_title

European journal of pharmacology

authors

Daniele E,Villani G,Lograno MD

doi

10.1016/s0014-2999(97)10122-4

subject

Has Abstract

pub_date

1997-07-09 00:00:00

pages

247-56

issue

2-3

eissn

0014-2999

issn

1879-0712

pii

S0014-2999(97)10122-4

journal_volume

330

pub_type

杂志文章

在线工具

Effects of phorbol ester on carbachol-induced contraction in bovine ciliary muscle: possible involvement of protein kinase C.