Dietary salt decreases cytosolic calcium in platelets from dahl
salt-sensitive rats.
Ishida, Takafumi, Mari Ishida, Hideo Matsuura, Ryoji Ozono, Goro
Kajiyama, Tetsuya Oshima.
First Department of Internal Medicine and Department of Clinical
Laboratory Medicine, Hiroshima University School of Medicine,
Hiroshima, Japan
APStracts 2:0161R, 1995.
To determine whether abnormal cellular Ca2+ handling is involved in
salt-induced hypertension of Dahl salt-sensitive rats (DS), we
investigated Ca2+ handling in fura-2-loaded platelets of DS and Dahl
salt-resistant rats (DR) fed a high (8%) or a low NaCl (0.3%) diet
for 4 weeks from 5 weeks of age. At 5 weeks of age, blood pressure,
resting cytosolic Ca2+ concentration ([Ca2+]i), the thrombin-evoked
increase in [Ca2+]i and the size of internal Ca2+ stores of DS were
comparable with those of DR. After 4 weeks on the diets, resting
[Ca2+]i of DS on high NaCl diet was lower than that of DS on low NaCl
diet, whereas there was no effect of high salt intake on resting
[Ca2+]i in DR. In DS, high salt intake attenuated the [Ca2+]i
response to thrombin in the presence of external Ca2+. In contrast,
the [Ca2+]i response to thrombin in the absence of external Ca2+ was
enhanced by high salt intake in DS. The size of internal Ca2+ stores
was increased by high salt intake in DS but not in DR. These data
suggest that it is not obligatory for hypertension to be accompanied
by an increase in platelet [Ca2+]i.
Received 17 May 1994; accepted in final form 6 June 1995
APS Manuscript Number R263-4.
Article publication pending Am. J. Physiol. (Regulatory Integrative
Comp. Physiology).
ISSN 1080-4757 Copyright 1995 The American Physiological Society.
Published in APStracts on 6 July 1995.