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A Comprehensive Method for the Quantitative Determination of Dopamine Receptor Subtypes a
Author(s) -
McGONIGLE PAUL,
HUFF RITA M.,
MOLINOFF PERRY B.
Publication year - 1984
Publication title -
annals of the new york academy of sciences
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.712
H-Index - 248
eISSN - 1749-6632
pISSN - 0077-8923
DOI - 10.1111/j.1749-6632.1984.tb14499.x
Subject(s) - medicine , library science , family medicine , gerontology , computer science
We have demonstrated that three subtypes of dopamine receptors can be characterized using several radioligand binding techniques. Indirect binding assays in which several competing ligands were used to inhibit the binding of the nonselective radioligand spiroperidol resulted in shallow displacement curves with Hill coefficients less than 1. Nonlinear regression analysis of these curves also indicated that there were two subtypes of the D-2 receptor present in a ratio of approximately 3 to 1. Direct binding assays with [3H]alpha-flupenthixol showed that this radioligand nonselectively labeled D-2A, D-2B, and D-1 receptors. Inhibition of the binding of [3H]alpha-flupenthixol by spiroperidol revealed that spiroperidol had a much higher affinity for D-2A and D-2B receptors than for D-1 receptors. Masking D-2 receptors with nanomolar concentrations of spiroperidol permitted characterization of D-1 receptors with the radioligand [3H]alpha-flupenthixol. Indirect binding assays of D-1 receptors with numerous competing ligands resulted in steep displacement curves with Hill coefficients of 1. This is consistent with the existence of a single, homogeneous population of D-1 receptors.