2006 Volume 42 Issue 4 Pages 131-138
The effects of aging on α1-adrenoceptor (α1-AR)-mediated contractile response in endothelium-removed aortic preparations isolated from 5- to 40-week-old (5-, 6-, 8-, 10-, 20-, 40-weeks) mice were studied in the presence of propranolol. The potency of noradrenaline, estimated as its pD2 value, increased with age from 5- to 10-weeks, but decreased thereafter with age from 10- to 40-weeks. However, the affinity of prazosin (pA2 value) did not change with aging. These results suggest that age-related change in noradrenaline potency is not attributable to the change of drug affinity to α1-ARs, but is possibly due to drug affinity-unrelated factors such as change of the reserve of α1-ARs.