Maturation and aging-related differences in responsiveness of rat aorta and carotid arteries to alpha1-adrenoceptor stimulation.
Functional correlates of alpha1-adrenoceptors were studied in thoracic aorta and carotid arteries from Wistar rats, at maturation (3- and 8-week-old) and aging (17- and 29-week-old) phases, using phenylephrine (PHE) and KCl. PHE and KCl effects on rat aorta did not differ with age. A reduction in maximal contractions to PHE or KCl occurred in carotid arteries during maturation. Concentration-inhibition curves to the alkylating agent chloroethylclonidine or WB4101 suggested at all ages studied a predominance of alpha1B-adrenoceptors in aorta. However, alpha1A-adrenoceptors may account for some activity in aortas of 29-week-old rats. In carotid arteries alpha1D-adrenoceptors account for functional correlates at all ages studied. The results indicate that maturation or aging affects vascular responsiveness or predominant receptor subtype differently in aorta and carotid arteries with intact endothelium.
de Oliveira
A M
AM
Laboratory of Pharmacology, School of Pharmaceutical Science, University of São Paulo, Ribeirão Preto, SP, Brazil. amolive@usb.br
Campos-Mello
C
C
Leitão
M C
MC
Correa
F M
FM
D000317:Adrenergic alpha-Antagonists / Q000494:pharmacology*; D000375:Aging / Q000502:physiology*; D000704:Analysis of Variance; D000818:Animals; D001013:Aorta, Thoracic / Q000187:drug effects / Q000502:physiology; D002339:Carotid Arteries / Q000187:drug effects / Q000502:physiology; D003000:Clonidine / Q000031:analogs & derivatives / Q000494:pharmacology; D004146:Dioxanes / Q000494:pharmacology; D004305:Dose-Response Relationship, Drug; D004347:Drug Interactions; D008297:Male; D009131:Muscle, Smooth, Vascular / Q000187:drug effects*; D010656:Phenylephrine / Q000494:pharmacology; D011189:Potassium Chloride / Q000494:pharmacology; D051381:Rats; D017208:Rats, Wistar; D018340:Receptors, Adrenergic, alpha-1 / Q000145:classification / Q000187:drug effects*; D014662:Vasoconstrictor Agents / Q000494:pharmacology*
D000317:Adrenergic alpha-Antagonists; D004146:Dioxanes; D018340:Receptors, Adrenergic, alpha-1; D014662:Vasoconstrictor Agents; D010656:Phenylephrine; C051731:chlorethylclonidine; D011189:Potassium Chloride; C010654:(2-(2',6'-dimethoxy)phenoxyethylamino)methylbenzo-1,4-dioxane; D003000:Clonidine