Quantitative Relationships of Five Putative Neurotransmitter Receptor Sites in Rat Hippocampal Formation

Abstract

The hippocampus reveals the interrelationships of various neurotransmitter systems in the CNS well due to its simple laminated organization, defined connections and variety of identified neurotransmitters. The biochemical and pharmacological properties of 5 radiolabeled ligand binding sites in a membrane fraction prepared from rat hippocampal formation were studied. These binding sites may identify recognition sites for neurotransmitter receptors. The rank order of ligand binding sites was [3H]muscimol > [3H]quinuclidinyl benzilate > [3H]dihydroergocryptine > [3H]dihydroalprenolol > 125I-labeled .alpha.-bungarotoxin. All ligands had a single, saturable, high-affinity binding site. Pharmacological characterization of the ligand binding sites indicates properties consistent with the identification of these sites as neurotransmitter receptors.