Region-specific decrease in 5-HT1A and 5-HT1B binding sites after intra-hippocampal ibotenic acid injections in the rat

The cellular location of 5-HT1A and 5-HT1B binding sites in the hippocampus was investigated using a stereotaxic unilateral lesion of the CA1 field by ibotenic acid, followed by autoradiography on brain sections with the spec ific ligands [H-3]8-OH-DPAT and S-CM-G[I-125]TNH2, respectively. As compare d to the contralateral side of the lesion, the ipsilateral side exhibited a decrease in the density of 5-HT1A binding sites in the strata oriens and r adiatum of CA1, and of 5-HT1B binding sites in the dorsal subiculum and str atum oriens of CA1. The results demonstrate that 5-HT1A binding sites are l ocated on dendrites whereas 5-HT1B binding sites are located on axon termin als of CA1 pyramidal cells. (C) 2001 Elsevier Science Ireland Ltd. All righ ts reserved.