Influence of dosage, consciousness, and nifedipine on the acute pressor response to intraperitoneally administered cadmium

The influence of blood pressure on intracellular Ca2+ content in erythrocytes: effects of cadmium chloride and nifedipine

Cellular abnormalities associated with elevated Ca2+ concentrations have been postulated to be involved in the pathogenesis of hypertension. The present study was undertaken to investigate the effects of blood pressure changes on cytosolic Ca2+ levels in erythrocytes. Cadmium, which has been implicated in the etiology of hypertension was used as the hypertensive agent and the classical blocker of voltage-operated calcium channels nifedipine was used to treat hypertension. 10 weeks old male rats were divided into four groups; control, CdCl2, CdCl2 and nifedipine, nifedipine groups. CdCl2 caused elevations in blood pressure and in the cytosolic erythrocyte Ca2+ levels both of which were reduced after nifedipine administration. After nifedipine alone, cytosolic Ca2+ levels were increased. These findings suggest that cytosolic Ca2+ content decreasing action of nifedipine in the CdCl2 and nifedipine applied group could be secondary to the antihypertensive action.

Prevention of spontaneous and glucocorticoid hypertension in rats by nisoldipine

The effect of daily treatment (sometimes interrupted) with the calcium blocker nisoldipine at two different dose levels, one double the other, on the development of spontaneous hypertension in the rat was evaluated. Both doses prevented development of the disorder during daily administration, but when treatment was stopped the same degree of hypertension as in controls quickly developed. Resumption of treatment caused blood pressure to fall to or towards normal again. The higher dose caused a more rapid and greater fall than the lower, and allowed a lesser pressor response when it was discontinued. The drug had no effect on growth, and the only consistent hematological effect was a slight thrombocytosis. Daily treatment at a single dose level slightly reduced normal blood pressure and prevented cortisone hypertension. Serum renin activity was unaffected by nisoldipine but was elevated by cortisone treatment: nisoldipine increased aldosterone levels, but not when cortisone was also given.