[Alteration of cardiac beta-adrenoceptors and subtypes with increasing age].
The alteration of cardiac beta-adrenoceptor (beta-AR) and subtypes in Wistar rats of 48 and 10 weeks old were investigated by radioligand binding assay and functional determination of isolated perfused left atria. The results indicated that: (1) The density of cardiac total beta-AR was downregulated about 28% in 48 weeks old rats as compared with rats of 10 weeks old for both beta 1- and beta 2-AR; (2) The sensitivity of beta-AR and subtypes to isoproterenol in isolated perfused atria was significantly lowered in rats of 48 weeks old; (3) The beta-AR mediated contractile effect of 10 weeks old rat hearts was mainly attributed to beta 1 type, but equally to both beta 1 and beta 2 types in 48 weeks old rat hearts; (4) The two receptor subtypes showed mutually potentiation effect in 10 weeks old rat hearts when stimulated simultaneously, but only additive in 48 weeks old rat hearts.
Li
Y F
YF
Institute of Vascular Medicine, Third Hospital, Beijing Medical University.
Zhang
Y Y
YY
Yi
Y M
YM
Han
Q D
QD
D000375:Aging / Q000378:metabolism*; D000818:Animals; D015536:Down-Regulation; D066298:In Vitro Techniques; D008297:Male; D009200:Myocardial Contraction; D009206:Myocardium / Q000378:metabolism*; D051381:Rats; D017208:Rats, Wistar; D011943:Receptors, Adrenergic, beta / Q000378:metabolism*; D018342:Receptors, Adrenergic, beta-1 / Q000378:metabolism; D018343:Receptors, Adrenergic, beta-2 / Q000378:metabolism
D011943:Receptors, Adrenergic, beta; D018342:Receptors, Adrenergic, beta-1; D018343:Receptors, Adrenergic, beta-2