Calcium channels in vitamin B6 deficiency-induced hypertension.
OBJECTIVE
To compare the acute hypotensive effects of various calcium channel modulators in vitamin B6-deficient hypertensive (B6DHT) rats.


METHODS
Adult male Sprague-Dawley rats were fed a vitamin B6-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 potency: nifedipine > (-)-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 B6 content of their diet was increased or removed for a short period.


CONCLUSIONS
Calcium channel function appears to be related to vitamin B6 status in the rat.
Lal
K J
KJ
Department of Biochemistry and Molecular Biology, Faculty of Medicine, University of Manitoba, Winnipeg, Canada.
Dakshinamurti
K
K
D001498:3-Pyridinecarboxylic acid, 1,4-dihydro-2,6-dimethyl-5-nitro-4-(2-(trifluoromethyl)phenyl)-, Methyl ester / Q000494:pharmacology; D000818:Animals; D001794:Blood Pressure / Q000187:drug effects; D002121:Calcium Channel Blockers / Q000494:pharmacology; D015220:Calcium Channels / Q000187:drug effects / Q000378:metabolism*; D004110:Diltiazem / Q000494:pharmacology; D006973:Hypertension / Q000188:drug therapy / Q000209:etiology* / Q000378:metabolism*; D008297:Male; D009539:Nicotinic Acids / Q000494:pharmacology; D009543:Nifedipine / Q000494:pharmacology; D010069:Oxadiazoles; D051381:Rats; D017207:Rats, Sprague-Dawley; D014700:Verapamil / Q000494:pharmacology; D026681:Vitamin B 6 Deficiency / Q000150:complications* / Q000378:metabolism* / Q000503:physiopathology
D002121:Calcium Channel Blockers; D015220:Calcium Channels; D009539:Nicotinic Acids; D010069:Oxadiazoles; C049834:PN 202-791; D001498:3-Pyridinecarboxylic acid, 1,4-dihydro-2,6-dimethyl-5-nitro-4-(2-(trifluoromethyl)phenyl)-, Methyl ester; D014700:Verapamil; D004110:Diltiazem; D009543:Nifedipine