MEASUREMENT OF GLYCINE RECEPTOR FUNCTION BY RADIOACTIVE CHLORIDE UPTAKE

The glycine receptor is an important inhibitory receptor for both spin al and supraspinal functions, and mutations in receptor subunits are r esponsible for neurological disorders in several species, including hu mans. However, functional measurements of glycine receptors have gener ally been restricted to electrophysiological analysis of immature, cul tured neurons. We developed a Cl-36(-) flux assay to measure glycine r eceptor function using membrane vesicles from spinal cord and brainste m of adult mice. The uptake of Cl-36(-) stimulated by glycine was char acterized by a glycine EC(50) of 22 mu M for the major component and a n EC(50) of 0.5 mu M for a minor component. Strychnine inhibited the g lycine-stimulated uptake with an IC50 of 0.4 mu M. The uptake was not affected by picrotoxin, bicuculline, or pentobarbital. Glycine-stimula ted uptake reached a maximum by 10 s. This technique should prove usef ul for genetic and pharmacological analysis of the function of glycine receptors.