Sensitivity to Ca2+ and the effects of a calcium channel antagonist in resistance vessels from two strains of genetically hypertensive rat.
Ca sensitivity and sensitivity to diltiazem were studied in two strains of genetically hypertensive rat [spontaneously hypertensive rats (SHRs) and genetically hypertensive (GH) rats] and their normotensive control strains [Wistar-Kyoto (WKY) and normal Wistar (N) rats] at two ages before and after establishment of significant hypertension. Ca sensitivity was equal in both hypertensive/normotensive strain pairs from young rats but significant relative increases in Ca sensitivity were present in older rats. Sensitivity to the vasodilating action of diltiazem in vessels precontracted using K+ was also present in adult rats. These results suggest that the abnormality in Ca sensitivity seen in genetic hypertension in rats is an acquired characteristic not involved in the etiology of hypertension.
Cassie
N J
NJ
Department of Pharmacology, University of Otago Medical School, Dunedin, New Zealand.
Cross
M A
MA
Phelan
E L
EL
Millar
J A
JA
D000818:Animals; D001808:Blood Vessels / Q000187:drug effects; D002118:Calcium / Q000494:pharmacology*; D002121:Calcium Channel Blockers / Q000494:pharmacology*; D004110:Diltiazem / Q000494:pharmacology; D008297:Male; D009119:Muscle Contraction / Q000187:drug effects; D011188:Potassium / Q000494:pharmacology; D051381:Rats; D011918:Rats, Inbred SHR; D011921:Rats, Inbred WKY; D014655:Vascular Resistance / Q000187:drug effects*
D002121:Calcium Channel Blockers; D004110:Diltiazem; D011188:Potassium; D002118:Calcium