Therapeutic Research

Abstract

Hypertension and insulin resistance or diabetes mellitus are frequently associated withcomplications, with stimulation of the sympathetic nervous system suggested as one of theunderlying mechanisms. Previously, we confirmed that the L－type／N－type calcium channelblocker（CCB）cilnidipine improved insulin resistance and increased adrenal androgen andadiponectin levels in patients with hypertension. The aims of the present study were to determinewhether these effects were maintained with long－term（＞1 year）cilnidipine administrationand whether inhibition of the sympathetic nervous system by cilnidipine was correlatedwith these improvements. When cilnidipine was administered to patients with essentialhypertension and insulin resistance or mild diabetes mellitus, significant decreases were observed in blood pressure and heart rate, insulin resistance improved, and adrenal androgenproduction increased. These improvements were maintained over the longer term（cilnidipinetreatment＞1 year）. We also investigated the relationship between the magnitude of theincrease in serum adiponectin levels and changes in heart rate and found a significant negativecorrelation between the two. This finding suggests that one of the mechanisms underlyingthe increase in serum adiponectin levels may be related to inhibition of the sympatheticnervous system by the N－type CCB. Our results suggest that cilnidipine may be a usefuldrug for the treatment of hypertension associated with metabolic abnormalities.