Age-associated alterations in catecholaminergic concentrations, neuronal activity, and alpha 1 receptor densities in female rats.

The density of alpha 1-adrenergic receptors and catecholamine concentrations and neuronal activity were assessed in selected estrogen-responsive regions of the hypothalamus and pineal glands. The results of this study demonstrate that the densities of alpha 1-adrenergic receptors and norepinephrine and epinephrine concentrations and activity rate constants are altered in aged rats. The direction and extent of the change depend on the specific brain region and reproductive state of the animals. No widespread decline with increased age was observed in any of the parameters measured.