Characterization of 5-HT(₁A,B) and 5-HT(₂A,C) serotonin receptor binding.

This unit describes assays for measuring the binding of radioligands to two major types of receptors for 5-hydroxytryptamine (5-HT or serotonin), 5-HT₁ and 5-HT₂ receptors, in homogenates of brain tissue or cloned into cells in culture. The specific receptor subtypes covered are 5-HT(₁A), 5-HT(₁B), 5-HT(₂A), and 5-HT(₂C). In addition, methodology for using quantitative autoradiography to measure radioligand binding to serotonin receptors in brain slices is described. Protocols are provided for characterization of both saturation and competition binding assays, and instructions for data analysis of these assays is also described. In addition, methodology is provided for the quantification (image analysis) of radioligand binding in brain tissue sections to determine receptor density, preparation of rat brain sections for quantitative autoradiography, and thionin staining of thaw-mounted tissue sections to define certain brain regions.