Relations of vascular calcium channels with blood pressure and endothelium in hypertension and with aging.
To investigate the relationships between the activity in potential operated Ca2+ channels (POC), blood pressure, and endothelium in hypertension, we tested the contractile responses to a Ca2+ channel agonist Bay K 8644 (BAY K) in aorta from deoxycorticosterone-acetate-saline (DOCA-S) and reduced renal mass-saline (RRM-S) hypertensive rats. The effects of mechanical rubbing, N omega-Nitro-L-Arginine Methyl Ester (l-NAME) and indomethacin were also examined. Sensitivity to BAY K increased in experimental rats before they became hypertensive and contractile responses were enhanced as hypertension developed. Force development to BAY K was correlated with blood pressure levels. Endothelium removal enhanced the contractile response to BAY K. L-NAME, but not indomethacin, potentiated the response to BAY K. Contractile response to BAY K was negatively correlated with relaxation to acetylcholine. An enhanced contractile response to BAY K was observed also in aged rats. Enhanced activation of vascular POC in hypertension results from elevated blood pressure and partly from diminished inhibitory action of endothelium. Senescence also enhances vascular POC activity.
Hui
C
C
Second Department of Internal Medicine, Faculty of Medicine, University of Tokyo, Japan.
Goto
A
A
Yamada
K
K
Yagi
N
N
Nagoshi
H
H
Sasabe
M
M
Omata
M
M
Sugimoto
T
T
D001498:3-Pyridinecarboxylic acid, 1,4-dihydro-2,6-dimethyl-5-nitro-4-(2-(trifluoromethyl)phenyl)-, Methyl ester / Q000494:pharmacology; D000375:Aging; D000818:Animals; D001794:Blood Pressure / Q000187:drug effects; D002120:Calcium Channel Agonists / Q000494:pharmacology; D015220:Calcium Channels / Q000187:drug effects; D003900:Desoxycorticosterone; D004195:Disease Models, Animal; D004730:Endothelium, Vascular / Q000187:drug effects / Q000503:physiopathology*; D006973:Hypertension / Q000139:chemically induced / Q000188:drug therapy / Q000503:physiopathology*; D008297:Male; D051381:Rats; D017208:Rats, Wistar; D014661:Vasoconstriction / Q000187:drug effects
D002120:Calcium Channel Agonists; D015220:Calcium Channels; D003900:Desoxycorticosterone; D001498:3-Pyridinecarboxylic acid, 1,4-dihydro-2,6-dimethyl-5-nitro-4-(2-(trifluoromethyl)phenyl)-, Methyl ester