TY - JOUR
T1 - Ovariectomy aggravated sodium induced hypertension associated with altered platelet intracellular Ca2+ in Dahl rats
AU - Otsuka, Keiichi
AU - Ohno, Yoichi
AU - Sasaki, Takayuki
AU - Yamakawa, Hiroshi
AU - Hayashida, Tomoko
AU - Suzawa, Taichi
AU - Suzuki, Hiromichi
AU - Saruta, Takao
N1 - Funding Information:
This work was supported by grants from National Rice Association (Tokyo, Japan), and the Japan Foundation for Aging and Health (Tokyo, Japan).
Copyright:
Copyright 2007 Elsevier B.V., All rights reserved.
PY - 1997/12
Y1 - 1997/12
N2 - Our purpose was to determine the effect of ovariectomy on intracellular Ca2+ mobilization and platelet aggregation in sodium induced hypertension. At the age of 12 weeks ovariectomy or sham operation was performed in female Dahl-Iwai salt sensitive rats on a 0.3% NaCl diet. Four weeks later we assessed the effects of ovariectomy and an 8% NaCl diet on agonist induced intracellular Ca2+ mobilization in fura-2 loaded platelets and platelet aggregation. Ovariectomy enhanced the increase of systolic blood pressure and heart to body weight ratio on an 8% NaCl diet. However, thrombin evoked intracellular Ca2+ was not correlated with systolic blood pressure (r = - 0.338, P = .17), and was lowered by sodium loading and ovariectomy (360 ± 23 to 285 ± 9, 296 ± 10 nmol/L, P < .05). Furthermore, the ionomycin induced intracellular calcium fraction in the absence of external Ca2+ that reflected internal Ca2+ discharge capacity was reduced in ovariectomized rats compared with sham operated rats on an 8% NaCl diet (648 ± 15 v 768 ± 35 nmol/L, P < .05). The internal Ca2+ discharge capacity was inversely correlated with systolic blood pressure (r = -0.506, P = .03). In addition to the decreased internal Ca2+ discharge capacity, intracellular Ca2+- independent platelet aggregation by phorbol 12-myristate 13-acetate, a protein kinase C activator, was significantly enhanced in hypertensive rats. We concluded that ovariectomy enhanced sodium induced hypertension associated with the decreased internal Ca2+ discharge capacity and increased platelet aggregation in Dahl-Iwai salt-sensitive rats.
AB - Our purpose was to determine the effect of ovariectomy on intracellular Ca2+ mobilization and platelet aggregation in sodium induced hypertension. At the age of 12 weeks ovariectomy or sham operation was performed in female Dahl-Iwai salt sensitive rats on a 0.3% NaCl diet. Four weeks later we assessed the effects of ovariectomy and an 8% NaCl diet on agonist induced intracellular Ca2+ mobilization in fura-2 loaded platelets and platelet aggregation. Ovariectomy enhanced the increase of systolic blood pressure and heart to body weight ratio on an 8% NaCl diet. However, thrombin evoked intracellular Ca2+ was not correlated with systolic blood pressure (r = - 0.338, P = .17), and was lowered by sodium loading and ovariectomy (360 ± 23 to 285 ± 9, 296 ± 10 nmol/L, P < .05). Furthermore, the ionomycin induced intracellular calcium fraction in the absence of external Ca2+ that reflected internal Ca2+ discharge capacity was reduced in ovariectomized rats compared with sham operated rats on an 8% NaCl diet (648 ± 15 v 768 ± 35 nmol/L, P < .05). The internal Ca2+ discharge capacity was inversely correlated with systolic blood pressure (r = -0.506, P = .03). In addition to the decreased internal Ca2+ discharge capacity, intracellular Ca2+- independent platelet aggregation by phorbol 12-myristate 13-acetate, a protein kinase C activator, was significantly enhanced in hypertensive rats. We concluded that ovariectomy enhanced sodium induced hypertension associated with the decreased internal Ca2+ discharge capacity and increased platelet aggregation in Dahl-Iwai salt-sensitive rats.
KW - Calcium
KW - Dahl rats
KW - Ovariectomy
KW - Platelet aggregation
KW - Protein kinase C
KW - Sodium
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U2 - 10.1016/S0895-7061(97)00312-9
DO - 10.1016/S0895-7061(97)00312-9
M3 - Article
C2 - 9443776
AN - SCOPUS:0031417264
SN - 0895-7061
VL - 10
SP - 1396
EP - 1403
JO - American Journal of Hypertension
JF - American Journal of Hypertension
IS - 12 I
ER -