Alterations of cytosolic calcium in platelets and erythrocytes of Lyon hypertensive rats.
Platelet cytosolic free calcium concentration ([Ca2+]i) and intracellular pH (pHi) (including their responses to thrombin), as well as erythrocyte [Ca2+]i and 45Ca2+ influx, were studied in Lyon hypertensive (LH) and normotensive (LN) rats aged 3 months. Platelets of LH rats were characterized by substantially elevated basal [Ca2+]i values, higher [Ca2+]i levels after thrombin stimulation, and enhanced initial rate of thrombin-induced Mn2+ entry through receptor-operated Ca2+ channels. Basal platelet pHi values were not significantly different in LH and LN animals but thrombin elicited a significant alkalinization only in LH platelets. Erythrocytes of LH rats had an enhanced initial rate of 45Ca2+ and tended to elevated [Ca2+]i levels. Our data indicate profound alterations in cell Ca2+ handling in platelets and erythrocytes of LH rats, similar to those previously described in spontaneously hypertensive rats of the Okamoto-Aoki strain. The analysis of the relations between blood pressure, plasma lipids, and cell Ca2+ handling suggested that triglycerides, but not cholesterol, might be involved in altered platelet Ca2+ handling in LH rats.
Zicha
J
J
Department of Pharmacology, URA CNRS 1482, Faculté de Médicine Necker, Paris, France.
Pernollet
M G
MG
Kunes
J
J
Lacour
B
B
Vincent
M
M
Sassard
J
J
Devynck
M A
MA
D000818:Animals; D001792:Blood Platelets / Q000187:drug effects / Q000378:metabolism*; D001794:Blood Pressure; D002118:Calcium / Q000097:blood*; D003600:Cytosol / Q000187:drug effects / Q000378:metabolism*; D004912:Erythrocytes / Q000187:drug effects / Q000378:metabolism*; D006863:Hydrogen-Ion Concentration; D006973:Hypertension / Q000097:blood* / Q000503:physiopathology; D007424:Intracellular Fluid / Q000187:drug effects / Q000378:metabolism*; D008055:Lipids / Q000097:blood*; D008297:Male; D051381:Rats; D013917:Thrombin / Q000494:pharmacology
D008055:Lipids; D013917:Thrombin; D002118:Calcium