Alterations of subtypes of cardiac adrenoceptors in old rat.
OBJECTIVE
To determine alterations of subtypes of myocardial adrenoceptors in senescence.


METHODS
Heart membrane preparations were made from 3- and 25-month old Wistar rats. Alpha 1- and beta-adrenoceptors were measured by radioligand, 125I-BE2254 and 125I-pindolol, binding assays, respectively.


RESULTS
In the old rat heart, alpha 1- and beta-adrenoceptor densities were declined from the young rats of 119 +/- 4 and 45.9 +/- 1.9 pmol L-1 to 70 +/- 6 and 36.4 +/- 1.6 pmol L-1 (P < 0.01), with a greater change in alpha 1-AR and in beta-AR. The ratio of alpha 1A/alpha 1B subtypes was decreased from the young rats of 39/61 to the old rats of 26/74 (P < 0.05).


CONCLUSIONS
The cardiac adrenoceptors are decreased with different extents in the different subtypes in old rats.
Yu
G S
GS
Institute of Vascular Medicine, Beijing Medical University, China.
Chen
M Z
MZ
Han
Q D
QD
D000375:Aging / Q000378:metabolism*; D000818:Animals; D009206:Myocardium / Q000378:metabolism*; D011869:Radioligand Assay; D051381:Rats; D017208:Rats, Wistar; D018340:Receptors, Adrenergic, alpha-1 / Q000145:classification / Q000378:metabolism*; D011943:Receptors, Adrenergic, beta / Q000378:metabolism*
D018340:Receptors, Adrenergic, alpha-1; D011943:Receptors, Adrenergic, beta