Abstract
Binding of [ 3H]thyrotropin-releasing hormone (TRH) to its receptors in the rat limbic forebrain was partially displaced by 5-hydroxytryptamine (5-HT, ligand for 5-HT 1 receptors) and (+)-lysergic acid diethylamide ((+)-LSD, ligand for 5-HT 1 and 5-HT 2 receptors) at nanomolar concentrations. Spiperone (ligand for 5-HT 2 receptors) displaced [ 3H]TRH in a dose-dependent manner at micromolar concentrations. These results suggest that some TRH receptors are related to 5-HT 1 receptors, probably adjoining them on the membrane. This type of TRH receptor is shown to be among the high-affinity receptors which we reported previously. The significance of the receptor-coexistence is such that TRH facilitates serotonergic transmission by increasing the density of 5-HT 1 receptors. This finding seems to support a pharmacological observation of other investigators that TRH potentiates 5-HT-induced hyperactivity in mice, probably by affecting postsynaptic 5-HT receptors.
Published Version
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a call