[The effect of endothelin-1 on Na+/H+ metabolism in vascular smooth muscle cells].
The effects of endothelin on intracellular pH (pHi) were examined in cultured rat vascular smooth muscle cells (VSMC) using the fluorescent probe BCECF. Endothelin induced biphasic changes in pHi: initial decrease followed by a subsequent increase above the basal level due to activation of the Na+/H+ exchange. The elevation of pHi was slow and sustained, but depended on the dose of endothelin: IC50 was about 3 x 10(-8) M. Na+/H+ exchange inhibition by EIPA (10(-7) M) or by equimolar replacement of external Na+ by choline abolished the pHi increase by enhancing the first phase of cytoplasm acidification. Effects of endothelin were compared with the action of protein kinase C (PK-C) activator phorbol 12-13 myristate ester (PMA). PMA induced a monophasic slow and sustained increase in pHi. The treatments of VSMC with H-7 and staurosporine (PK-C) inhibitors prevented the pHi response to endothelin and PMA. These results suggest that protein kinase C may play an important role in mediating the effects of endothelin on Na+/H+ exchange in VSMC.
Pinelis
V G
VG
Lonchampt
M O
MO
Shulz
J
J
Markov
Kh M
KhM
Chabrier
E
E
Braquet
P
P
D000818:Animals; D002478:Cells, Cultured / Q000187:drug effects / Q000378:metabolism; D004305:Dose-Response Relationship, Drug; D016232:Endothelins / Q000494:pharmacology*; D005452:Fluoresceins; D005456:Fluorescent Dyes; D006859:Hydrogen / Q000378:metabolism*; D006863:Hydrogen-Ion Concentration; D009131:Muscle, Smooth, Vascular / Q000166:cytology / Q000187:drug effects* / Q000378:metabolism; D010703:Phorbol Esters / Q000494:pharmacology; D051381:Rats; D011921:Rats, Inbred WKY; D012964:Sodium / Q000378:metabolism*
D016232:Endothelins; D005452:Fluoresceins; D005456:Fluorescent Dyes; D010703:Phorbol Esters; D006859:Hydrogen; C043829:2',7'-bis(carboxyethyl)-5(6)-carboxyfluorescein; D012964:Sodium
Vliianie éndotelina-1 na Na+/H(+)-obmen v gladkomyshechnykh kletkakh sosudov.