Contractile responses of rat aorta to phenylephrine and serotonin, and aging.
1. The potency (pD2 value) of phenylephrine increased with age from 3 to 10 weeks, but decreased thereafter from 10 to 80 weeks, while the affinity (pKA value) of phenylephrine to alpha 1-adrenoceptors did not alter with aging. 2. The potency (pD2 value) of serotonin did not alter with aging. 3. There is no significant difference between slopes of regression lines between a cytosolic free Ca2+ level ([Ca2+]i) and tension in the presence of phenylephrine in aorta strips from 10- and 60-week-old rats, suggesting that the sensitivity of contractile system to Ca2+ did not alter with aging. 4. Effect of ryanodine on the transient increase of [Ca2+]i and the followed sustained contraction induced by phenylephrine or serotonin in Ca2+ free solution did not alter with aging.
Takayanagi
I
I
Department of Chemical Pharmacology, Toho University School of Pharmaceutical Sciences, Chiba, Japan.
Onozuka
S
S
Ohtsuki
H
H
Shinkai
M
M
D000375:Aging / Q000187:drug effects / Q000502:physiology*; D000818:Animals; D001013:Aorta, Thoracic / Q000187:drug effects; D002110:Caffeine / Q000494:pharmacology; D002118:Calcium / Q000378:metabolism; D016257:Fura-2; D066298:In Vitro Techniques; D007537:Isometric Contraction / Q000187:drug effects; D008297:Male; D009119:Muscle Contraction / Q000187:drug effects; D009131:Muscle, Smooth, Vascular / Q000187:drug effects*; D010656:Phenylephrine / Q000494:pharmacology*; D011188:Potassium / Q000494:pharmacology; D051381:Rats; D011919:Rats, Inbred Strains; D012433:Ryanodine / Q000494:pharmacology; D012701:Serotonin / Q000494:pharmacology*
D012433:Ryanodine; D010656:Phenylephrine; D012701:Serotonin; D002110:Caffeine; D011188:Potassium; D002118:Calcium; D016257:Fura-2