Quantitative studies of N-methyl-D-aspartate, 2-amino-5- phosphonovalerate and cis-2,3-piperidine dicarboxylate interactions on the neonatal rat spinal cord in vitro

A quantitative study of the actions of excitatory amino acids and antagonists in rat hippocampal slices

“…Other studies have indicated that APV is without effect on non-amino acid excitants (Davies et al, 1981;Collingridge et al, 1983a;Childs et al, 1987). In spinal cord and cortex, APV has been found to be a competitive antagonist of NMDA with a Schild slope of 1.0 and a pA2 value usually of between 5.0 and 5.4 (Evans et al, 1982;Harrison & Simmonds, 1985;Wheatley & Collins, 1986). The apparent pA2 of 5.21 obtained in the present experiments is consistent with these previous studies and suggests a similarity between the affinities of NMDA receptors present in different areas of the central nervous system (of the rat).…”

“…The hippocampus is more sensitive to NMDA than the spinal cord (Martin & Lodge, 1985;Wheatley & Collins, 1986), cerebellum (Garthwaite et al, 1986) and other cortical regions (Harrison & Simmonds, 1985;Surtees & Collins, 1985;Wong et al, 1986;Martin & Lodge, 1987), whether expressed in terms of absolute potency or as potency relative to excitatory amino acids acting at non-NMDA receptors. This greater sensitivity may be due to the particularly high density of NMDA receptors in the CA1 region of the hippocampus (Cotman et al, 1987).…”

“…Harrison & Simmonds, 1985;Martin & Lodge, 1985;Wheatley & Collins, 1986); the mean apparant pA2 value was 5.21 + 0.04 (11).…”

Primary afferent activity, putative excitatory transmitters and extracellular potassium levels in frog spinal cord.

“…Kudo & Fukuda, 1976;Evans, 1980;Sonnhof & Biihrle, 1980;Pumain & Heinemann, 1985). In addition, kynurenate and APV, specific antagonists of the postsynaptic actions of excitatory amino acids (Davies et al 1982;Jahr & Yoshioka, 1986;Wheatley & Collins, 1986), reduced A[K+]o evoked by trains of afferent volleys.…”

“…For example, in Mg2+-free medium, NMDA produced dose-dependent increases in [K+]o. Furthermore, APV, when applied in a concentration that selectively antagonizes NMDA responses in in vitro spinal cord preparations (Wheatley & Collins, 1986), reduced A[K+]. by about 50%.…”