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Hippocampal 8‐[ 3 H]Hydroxy‐2‐(Di‐ n ‐Propylamino)Tetralin Binding Site Densities, Serotonin Receptor (5‐HT 1A ) Messenger Ribonucleic Acid Abundance, and Serotonin Levels Parallel the Activity of the Hypothalamopituitary‐Adrenal Axis in Rat
Author(s) -
Burnet Philip W. J.,
Mefford Ivan N.,
Smith Craig C.,
Gold Philip W.,
Sternberg Esther M.
Publication year - 1992
Publication title -
journal of neurochemistry
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.75
H-Index - 229
eISSN - 1471-4159
pISSN - 0022-3042
DOI - 10.1111/j.1471-4159.1992.tb08348.x
Subject(s) - endocrinology , medicine , serotonin , adrenalectomy , hippocampal formation , hippocampus , 5 ht receptor , receptor , chemistry , biology
We have previously demonstrated that susceptibility of the Lewis rat to inflammatory disease, compared with the relatively resistant Fischer F344/N rat, is related to a hyporesponsive hypothalamopituitary‐adrenal axis to inflammatory and other stress mediators. Because serotonin (5‐HT) and the 5‐HT 1A receptor are important stimulators of this axis, we have investigated the levels of 8‐[ 3 H]‐hydroxy‐2,3‐(di‐ n ‐propylamino)tetralin binding sites, 5‐HT 1A mRNA, 5‐HT, and 5‐hydroxyindoleacetic acid in various brain regions of Lewis, outbred Harlan Sprague Dawley, and Fischer F344/N rats. Lewis rats expressed significantly fewer hippocampal and frontal cortical 8‐[ 3 H]‐hydroxy‐2,3‐(di‐ n ‐propylamino)tetralin binding sites and less 5‐HT 1A mRNA than Harlan Sprague Dawley and Fischer F344/N rats. Adrenalectomy increased the number of 8‐[ 3 H]hydroxy‐2,3‐(di‐ n ‐propylamino)tetralin binding sites and 5‐HT 1A mRNA expression in the hippocampus of all three strains. Levels of hippocampal 5‐HT in Fischer F344/N rats were significantly greater than levels detected in the same regions from Lewis and Harlan Sprague Dawley rats. Hypothalamic 5‐HT and 5‐hydroxyindoleacetic acid levels in Harlan Sprague Dawley rats were higher than the same area from the other two strains. Adrenalectomy increased the levels of 5‐hydroxyindoleacetic acid in the hypo‐thalamus of all three strains. We conclude that hippocampal 5‐HT 1A receptor densities and 5‐HT levels in the rat parallel the activity and responsiveness of the hypothalamopituitary‐adrenal axis.