In vivo and in vitro effects of isradipine on cytosolic Ca2+ concentration in erythrocytes from spontaneously hypertensive rats.
Cytosolic Ca2+ concentration ([Ca2+]i) was investigated in erythrocytes from spontaneously hypertensive rats (SHR) and their normotensive controls (WKY), after an acute treatment with the Ca2+ antagonist isradipine. Blood samples were obtained from conscious rats and [Ca2+]i measured with fura-2. The [Ca2+]i was higher in SHR than in WKY erythrocytes (P < .05). Isradipine administration had no effect on WKY [Ca2+]i, but reduced that of SHR to WKY levels after 1 h. In vitro, isradipine dose-dependently decreased [Ca2+]i only in SHR (P = .006). The reduction by isradipine of the elevated [Ca2+]i in SHR suggests the presence of a greater dihydropyridine-sensitive Ca2+ influx in the SHR erythrocyte.
Morris
M J
MJ
Department of Pharmacology, CNRS URA 1482, Necker Medical School, Paris, France.
Dufilho
M D
MD
Devynck
M A
MA
D000818:Animals; D002118:Calcium / Q000097:blood*; D003600:Cytosol / Q000737:chemistry*; D004912:Erythrocytes / Q000737:chemistry* / Q000648:ultrastructure; D006973:Hypertension / Q000097:blood* / Q000503:physiopathology; D017275:Isradipine / Q000494:pharmacology*; D008297:Male; D051381:Rats; D011918:Rats, Inbred SHR; D011921:Rats, Inbred WKY
D002118:Calcium; D017275:Isradipine