Up-regulation of muscle uncoupling protein 3 gene expression by calcium channel blocker, benidipine hydrochloride in rats.

To examine whether benidipine hydrochloride, one of the calcium channel blockers, up-regulate uncoupling protein 3 (UCP3) expression in two skeletal muscles (gastrocnemius and soleus) in rats. Wistar rats were treated orally with benidipine hydrochloride at 4 mg/kg for 7 days. Blood pressure was measured after 4 days. At the end of experiments, the rats were weighed, and brown adipose tissue (BAT) and skeletal muscles (gastrocnemius and soleus muscles) were removed. The mRNA levels of uncoupling protein 1 (UCP1) and UCP3 were measured using the real-time quantitative reverse transcription-polymerase chain reaction method. Benidipine reduced body weight and also had a hypotensive effect. In rats treated with benidipine, UCP1 mRNA levels were significantly increased 1.4-fold in BAT, and UCP3 mRNA levels in BAT and gastrocnemius muscle were significantly increased 1.7 and 3.0-fold, respectively, compared with the control rats. There was no difference in UCP3 mRNA levels in soleus muscle between the two groups. We concluded that benidipine up-regulates not only UCP1 gene expression in BAT but also UCP3 gene expression in BAT and gastrocnemius muscle, which may contribute to thermogenesis in rats.