Calcium channels in vitamin B6 deficiency-induced hypertension

OBJECTIVE:To compare the acute hypotensive effects of various calcium channel modulators in vitamin B-deficient hypertensive (B6DHT) rats METHODS:Adult male Sprague-Dawley rats were fed a vitamin B-deficient diet for 7-10 weeks, during which systolic blood pressure (SBP) was measured in the B6DHT and control rats, using tail-cuff plethysmography. The effects of the calcium antagonists nifedipine, verapamil, diltiazem and (-)-202-791 on SBP were determined in conscious B6DHT rats. The effect of the calcium agonist BAY K 8644 on the SBP of rats fed various levels of pyridoxine was also determined RESULTS:All of the calcium antagonists used were effective in lowering the SBP of the B6DHT rats with the rank order of potencynifedipine>(-)-202-791>(±)-verapamil >diltiazem. BAY K 8644 elevated the SBP of older rats fed a normal commercially available diet, but had no effect when the vitamin B content of their diet was increased or removed for a short period CONCLUSION:Calcium channel function appears to be related to vitamin Bstatus in the rat