Nimodipine potentiates the light-induced suppression of melatonin

Changes in iNOS activity, oxidative stress and melatonin levels in hypertensive patients treated with lacidipine

OBJECTIVE(S)

To study the changes in macrophage inducible nitric oxide synthase (iNOS) activity, plasma levels of nitrite, lipid peroxidation (LPO) and melatonin in human essential hypertension before and 6 months after 4 mg/day lacidipine treatment.

DESIGN

The study was carried out in a total of 25 subjects--11 healthy subjects and 14 hypertensive patients. Blood pressure and peripheral blood samples were taken before and after 6 months of lacidipine treatment (4 mg/day).

METHODS

Systolic (SBP) and diastolic blood pressure (DBP), renal function, lipid and carbohydrate metabolism, renin, aldosterone and catecholamine levels were measured by routine methods. The activity of macrophage iNOS and plasma nitrite, LPO and melatonin levels were also measured.

CONCLUSIONS

Besides reducing blood pressure, lacidipine treatment significantly decreased plasma LPO and macrophage iNOS activity, without changes in NO. Melatonin significantly increases in hypertensive patients, returning to control after lacidipine. Thus, lacidipine reduced blood pressure and free radicals, avoiding the oxidative damage to endothelium. It is suggested that administration of lacidipine plus melatonin may enhance the beneficial effects of each drug in essential hypertension.

Nimodipine potentiates light-induced phase shifts of circadian activity rhythms but not c-fos expression in the suprachiasmatic nucleus of mice

The present study assessed whether treatment with the L-type calcium channel antagonist nimodipine affects the responsiveness of the circadian pacemaker to light in C3H/HeN mice. Nimodipine (10 mg/kg, sc) increased the magnitude of light-induced phase delays (P<0.01) and c-fos mRNA expression in the paraventricular nuclei (P<0.01), but not in the suprachiasmatic nuclei (SCN). These results suggest that nimodipine may affect phase shifts of circadian activity rhythms through a mechanism independent of c-fos expression in the SCN.