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Modulation of ( sup 3 H)-glutamate binding by serotonin in the rat hippocampus: An autoradiographic study

Journal Article · · Life Sciences; (United States)
;  [1]
  1. Istituto do Ricerche Farmacologiche Mario Negri, Milan (Italy)

Serotonin (5-HT) added in vitro increased ({sup 3}H)-glutamate specific binding in the rat hippocampus, reaching statistical significance in layers rich in N-Methyl-D-Aspartate sensitive glutamate receptors. This effect was explained by a significant increase in the apparent affinity of ({sup 3}H)-glutamate when 5-HT is added in vitro. Two days after lesion of serotonergic afferents to the hippocampus with 5,7- Dihydroxytryptamine ({sup 3}H)-glutamate binding was significantly decreased in the CA3 region and stratum lacunosum moleculare of the hippocampus, this reduction being reversed by in vitro addition of 10 {mu}M 5-HT. The decrease observed is due to a significant reduction of quisqualate-insensitive (radiatum CA3) and kainate receptors (strata oriens, radiatum, pyramidal of CA3). Five days after lesion ({sup 3}H)-glutamate binding increased significantly in the CA3 region of the hippocampus but was not different from sham animals in the other hippocampal layers. Two weeks after lesion ({sup 3}H)-glutamate binding to quisqualate-insensitive receptors was increased in all the hippocampal layers, while kainate and quisqualate-sensitive receptors were not affected. These data are consistent with the possibility that 5-HT is a direct positive modulator of glutamate receptor subtypes.

OSTI ID:
5410622
Journal Information:
Life Sciences; (United States), Journal Name: Life Sciences; (United States) Vol. 49:4; ISSN 0024-3205; ISSN LIFSA
Country of Publication:
United States
Language:
English