
%0 Journal Article
%A Kusaka, M 
%A Sperelakis, N 
%T Stimulation of Ca2+ current by phorbol esters in rat myometrial cells is dependent on intracellular Ca2+ concentration
%J Reproduction, Fertility and Development
%D 1996/12/01
%V 8
%N 8
%P 1147-1152
%K 
%R https://doi.org/10.1071/RD9961147
%U https://www.publish.csiro.au/paper/RD9961147 
%X The effects of phorbol esters on the L-type Ca2+ current (ICa(L)) were investigated using nystatin-perforated patch and standard whole-cell voltage clamp in uterine smooth muscle cells isolated from late-pregnant rats. Using nystatin-perforated patch to maintain the integrity of the cytosol components, phorbol 12-myristate 13-acetate (PMA, 300 nM) increased ICa(L). When the standard whole-cell voltage clamp was used, the effect of PMA was dependent on the Ca2+ concentration in the pipette solution: PMA enhanced ICa(L) at pCa 6 and pCa 7 but not at pCa 10 or pCa 8. The effect of PMA was reversed by a selective inhibitor of protein kinase C, calphostin-C (500 nM). It is concluded that phorbol esters stimulate ICa(L) in uterine muscle cells and that the isoform of protein kinase C involved in this effect is Ca2+ dependent. This mechanism may be involved in the regulation of uterine contraction during pregnancy. 
