Effects of glycine antagonists on Mg(2+)- and glycine-induced [3H]N-(1-[2-thienyl]cyclohexyl)-3,4-piperidine binding.

We investigated the effects of glycine antagonists, 3-amino-1-hydroxy-2- pyrrolidone (HA-966), 7-chlorokynurenic acid (7-Cl-KYNA), 6-cyano-7-nitroquinoxaline-2,3-dione (CNQX), 6,7-dichloro-3-hydroxy-2-quinoxalinecarboxylic acid (DHQXC), 6,7-dichloroquinoxaline-2,3-dione (DCQX), and 5-chloro-indole-2-carboxylic acid (5-Cl-I2CA), on Mg(2+)- and glycine-induced [3H]N-(1-[2-thienyl]cyclohexyl)-3,4-piperidine ([3H]TCP) binding to well-washed rat cortical membranes. Except for 5-Cl-I2CA, all the glycine antagonists completely inhibited not only glycine- but also Mg(2+)-induced [3H]TCP binding in a concentration-dependent manner. Out of all the glycine antagonists examined DHQXC most selectively inhibited Mg(2+)-induced [3H]TCP binding, while DCQX was the most selective for inhibiting glycine-induced [3H]TCP binding.