The distribution of serotonergic 5-HT1A and non-5-HT1A recognition sites along the dorso-ventral axis of the rat hippocampus
Kiedrowski, L.
Polish Journal of Pharmacology and Pharmacy 43(2): 103-113
1991
ISSN/ISBN: 0301-0244 PMID: 1946036 Document Number: 380875
The distribution of serotonergic 5-HT1 binding sites along the hippocampal dorso-ventral axis was compared with [3H]5-HT uptake considered as a marker of the quantity of serotonergic nerve terminals. [3H]5-HT binding to 5-HT1A and non-5-HT1A sites, of high and low affinity for spiperone, respectively, was investigated in three parts of the hippocampus: dorsal, medial and ventral. In each hippocampal part, 5-HT1A sites constituted approximately 70% of binding sites. [3H]5-HT uptake and [3H]5-HT binding to 5-HT1A and non-5-HT1A sites were significantly higher in the ventral than in the dorsal part of the hippocampus. The dorso-ventral hippocampal gradient in [3H]5-HT binding to both 5-HT1A and non-5-HT1A sites was due to an increase of the density (Bmax) of these sites along the longitudinal hippocampal axis, but not their affinity (Kd) for [3H]5-HT. The results are discussed in the context of the previously described mismatch between the localization of serotonergic nerve terminals and serotonergic receptors in the hippocampus.