Effects of nitrendipine on capacity of calcium binding of erythrocyte membrane and total intraerythrocyte calcium content in SHR rats.
OBJECTIVE
To study the effect of nitrendipine (Nit) on the capacity of calcium binding of erythrocyte membrane and total intraerythrocyte calcium content in spontaneous hypertensive rats (SHR).


METHODS
Systolic blood pressure (SBP) of the conscious rats was monitored by tailcuff method with a BP and HR recorder for MRS-III rat. Erythrocyte membrane was prepared according to modified Bing's method. Calcium binding of membrane and total intraerythrocyte calcium content was determined by an automatic absorption spectrophotometer. The membrane protein was determined with a colorimetric method.


RESULTS
Nit (ig 10 mg.kg-1 qd x 20 d) induced a significant reduction in total intraerythrocyte calcium content (169 +/- 18 vs 87 +/- 14 mumol/L cell, P < 0.01) accompanied by a marked fall of SBP (27.1 +/- 2.5 vs 16.7 +/- 1.0 kPa, P < 0.01) but exerted no influence on the capacity of calcium binding of erythrocyte membrane under incubation in CaCl2(0) (basal calcium binding) or 40 mmol.L-1 (maximal calcium binding) (21.9 +/- 2.3 vs 22.7 +/- 2.1 and 55 +/- 14 vs 53 +/- 23 mumol/g protein, respectively, P > 0.05).


CONCLUSIONS
The antihypertensive effect of Nit is related to the reduction of intracellular calcium and possibly have no direct relation to the capacity of calcium binding of cell membrane.
Wang
Y L
YL
Department of Pharmacology, Nanjing Medical University, China.
Tang
G Z
GZ
Ding
J H
JH
Li
D X
DX
D000818:Animals; D000959:Antihypertensive Agents / Q000494:pharmacology*; D001794:Blood Pressure / Q000187:drug effects; D002118:Calcium / Q000378:metabolism*; D002121:Calcium Channel Blockers / Q000494:pharmacology*; D004910:Erythrocyte Membrane / Q000378:metabolism*; D004912:Erythrocytes / Q000378:metabolism*; D005260:Female; D006973:Hypertension / Q000378:metabolism; D008297:Male; D009568:Nitrendipine / Q000494:pharmacology*; D051381:Rats; D011918:Rats, Inbred SHR; D011921:Rats, Inbred WKY
D000959:Antihypertensive Agents; D002121:Calcium Channel Blockers; D009568:Nitrendipine; D002118:Calcium