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Effects of hippocampal and amygdalar stimulation on uptake and binding of 3 H‐hydrocortisone in the hypothalamus of the cat
Author(s) -
Stith Rex D.,
Person Robert J.,
Dana Richard C.
Publication year - 1976
Publication title -
journal of neuroscience research
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.72
H-Index - 160
eISSN - 1097-4547
pISSN - 0360-4012
DOI - 10.1002/jnr.490020409
Subject(s) - hypothalamus , hippocampal formation , stimulation , endocrinology , hydrocortisone , medicine , chemistry , neuroscience , biology
Stimulation of the hippocampus or amygdala of adrenalectomized cats occurred for 10 sec followed by a 50 sec period of no stimulation, beginning 30 min prior to and ending 30 min after administration of 100 μCi of 3 H‐hydrocortisone into a lateral ventricle. Sixty min after administration of labeled hormone, the hypothalamus was excised and homogenized. Cytosol and nuclear extract fractions were obtained and analyzed for radioactivity and protein content. Separation of bound from free hydrocortisone was achieved by charcoal adsorption assay. Results reveal that stimulation of the hippocampus resulted in a greater concentration of 3 H‐hydrocortisone taken up into hypothalamic cells. Also, a greater percentage of total hormone found in the nuclear extract was assayed as bound 3 H‐hydrocortisone, and the concentration of bound radioactivity in the nuclear extract was increased over control values. Amygdalar stimulation, in general, yielded results similar to those obtained from control cats. However, although a lesser percentage of total hormone in the hypothalamic cytosol was assayed as bound hormone, there was a greater concentration of nuclear bound hormone than in controls, but less than that determined in the hippocampal stimulation group. These results add to the evidence that hippocampus and amygdala have a modulating influence upon the hypothalamo‐hypophyseal axis. They also suggest that one manner in which these limbic structures may influence hypothalamic function is to modulate the uptake and binding of hydrocortisone in hypothalamic cells.