Strychinine binding associated with synaptic glycine receptors in rat spinal cord membranes: ionic influences.

Ammonium salts of some anions decrease the potency of glycine in inhibiting (3H)strychnine binding associated with synaptic glycine receptors. A correspondence exists between the ability of the ammonium salts of anions to increase the IC50 of glycine in inhibiting the (3H) strychnine binding, their capacity to reduce the (3H) strychnine binding itself, and their capacity to reverse inhibitory postsynaptic potentials. The decrease of (3H)strychnine binding in the presence of chloride is abolished by sodium, while the decrease of the potency of glycine in inhibiting (3H)strychnine is not. Binding of (3H)strychnine is influenced by monovalent cations in a biphasic fashion. Concentrations of Li+, K+, and Na+ up to 150mM decrease (3H)strychnine binding, while higher concentrations of the cations increase (3H)strychnine binding. Inhibition by glycine of (3H)strychnine binding is enhanced by low concentrations of these cations.