Age-dependent changes in beta-adrenoceptor function in human detrusors and possible mechanisms.
- Author:
Gang LI
1
;
Kai LI
;
Zhenhua LI
;
Ping WANG
Author Information
- Publication Type:Journal Article
- MeSH: Adrenergic beta-Agonists; pharmacology; Age Factors; Aged; Aging; physiology; Female; Humans; Male; Middle Aged; Muscle Contraction; physiology; Muscle, Smooth; physiology; Radioligand Assay; Receptors, Adrenergic, beta; physiology; Urinary Bladder; physiology
- From: Chinese Medical Journal 2003;116(10):1511-1514
- CountryChina
- Language:English
-
Abstract:
OBJECTIVETo study age-dependent changes in beta-adrenergic responsiveness and their possible mechanisms.
METHODSResponsiveness to the beta-adrenergic agonists isoprenaline, BRL37344, forskolin, and dibutyryl cyclic AMP (DBcAMP) was examined in samples from 10 older patients by using a cellular function test. A radioligand binding assay was performed using the non-selective beta-adrenergic receptor ligand [3H]-dihydroalprenolol ([3H]-DHA). Specimens from 10 young men were used as controls.
RESULTSThere were no age-dependent changes in contractile response to KCl. The relaxation responses to isoprenaline, BRL37344, and forskolin decreased in the aged group by 15.0%, 17.6%, and 12.6%, respectively (P < 0.001). The pD2 values for isoprenaline and BRL37344 also declined significantly. There was no difference in the responsiveness to dibutyryl cyclic AMP (DBcAMP) between the two groups; the maximum binding site decreased significantly with increasing age, but the equilibrium-dissociation constant did not change.
CONCLUSIONSThere is an age-related decline in beta-adrenergic responsiveness which might be one of the causative factors of reduced bladder compliance in the elderly. A decrease in cAMP level caused by reduced receptor density and adenylyl cyclase activity might be the underlying molecular mechanism of the changes in beta-adrenergic responsiveness.
