Age-related dendritic growth in dentate gyrus of human brain is followed by regression in the 'oldest old'.

Dendritic extent in dentate gyrus granule cells of normal aging human brain was found to increase between middle age (fifties) and early old age (seventies). However, dendritic regression was found in the oldest old (nineties). This finding of dendritic regression following growth is in contrast to previous quantitative reports of continued dendritic growth in parahippocampal gyrus of aging human brain. This new result reinforces the concept of age and region specificity in changes in dendritic extent.

[3H]corticosterone binding in the caudate-putamen.

Autoradiographic data indicate little specific binding of corticosterone in the caudate-putamen. However, chronic glucocorticoid treatment has been reported to alter certain biochemical parameters within the caudate-putamen, including high-affinity choline uptake. We asked whether glucocorticoid receptors in the caudate-putamen of adrenalectomized rats could be detected by a biochemical approach. We determined the amount of specific [3H]corticosterone binding in cytosols from the caudate-putamen and the ability of nuclei in this brain region to retain [3H]corticosterone in vivo. Results indicated that 72 h post-adrenalectomy, the caudate-putamen has 56% of the maximal binding capacity of the hippocampus (205 +/- 11 vs 361 +/- 19 fmol/mg protein). The apparent Kd of [3H]corticosterone in the two tissues did not differ substantially. The cytosolic binding capacity of the caudate-putamen was similar to that of the cerebellum, a brain region which also fails to demonstrate marked retention of glucocorticoids in autoradiographic studies. When cytosol binding was measured at a shorter time period after adrenalectomy (12 h), no differences were observed between the binding capacities of the hippocampus and the caudate-putamen. In competition experiments using [3H]corticosterone as ligand, no differences between the caudate-putamen and the hippocampus were found in the relative affinities of any of 8 steroids; the order of relative affinities obtained was in good agreement with those reported for the classical glucocorticoid receptor in other tissues. Rats were injected via the tail vein with [3H]corticosterone, 36 nmol/kg, an amount calculated to saturate more than half the nuclear sites.(ABSTRACT TRUNCATED AT 250 WORDS)