Pharmacological characterization of D‐aminophosphonovaleric acid antagonism of amino acid and synaptically evoked excitations on frog motoneurones in vitro: an intracellular study

Abstract

1The effect of D-aminophosphonovaleric acid (D-APV) on the depolarizations induced by Nmethyl-D-aspartate (NMDA), glutamate, aspartate or quisqualate was studied with intracellular recordings from frog motoneurones in vitro.

Antagonism of synaptic potentials in ventral horn neurones by 6‐cyano‐7‐nitroquinoxaline‐2,3‐dione: a study in the rat spinal cord in vitro

“…The results of this study with CNQX do not contradict this but also suggest that it may be simplistic and that a significant component of polysynaptic transmission, at least onto ventral horn neurones, is relayed via non-NMDA receptors such as AMPA/quisqualate or kainate type. Similarly, on the basis of evidence presented here and other studies (Corradetti et al, 1985;Dale & Roberts, 1985;Forsythe & Westbrook, 1988), a case can be made for involvement of NMDA receptors in short latency mono-or di-synaptic responses. Ultimately, independent classes of muscle or cutaneous afferents and the involvement of the different types of amino acid receptors in transmission onto second order dorsal or ventral horn neurones must be analysed separately rather than collectively since it is likely that differences exist.…”

“…Such a result may be explained by postulating a minor NMDA receptor-mediated contribution to the synaptic activation of motoneurones by low threshold Group I and II afferents. A role for NMDA receptors in monosynaptic transmission has been demonstrated in vertebrate spinal cord (Corradetti et al, 1985;Dale & Roberts, 1985) and in cultured hippocampal and spinal neurones (Forsythe & Westbrook, 1988). In a population of dorsal horn neurones, D-AP5 reduced the peak amplitude of A deltaevoked monosynaptic e.p.s.ps by around 20% (Yoshimura & Jessel, 1990).…”

Contribution of NMDA and non–NMDA glutamate receptors to locomotor pattern generation in the neonatal rat spinal cord

“…NMDA receptors were blocked by bath application of 20 µM APV (n l 7) or 10 µM CPP (n l 6). Although these concentrations are known to result in complete blocking of NMDA receptors (Corradetti et al 1985 ;Jiang et al 1990 ;Pinco & Lev-Tov 1993 ;Trueblood et al 1996), we performed direct tests to confirm such a block in the present experimental conditions. To this end we examined the effects of bath application of 10 µM NMDA (n l 6) before, during, and after application of these antagonists.…”

The 1980s: d-AP5, LTP and a Decade of NMDA Receptor Discoveries

“…Most of the above studies were performed on rats or other mammals, although NMDA receptor-mediated d -AP5-sensitive synaptic excitation was earlier demonstrated in the spinal cord of amphibians [ 117 – 119 ] and of fish [ 120 , 121 ] and in the retina of fish [ 122 , 123 ]. Interestingly, superfusion of the exposed spinal cord with NMDA is able to initiate fictive locomotion in both frogs and lampreys, a pattern blocked by d -AP5 [ 118 , 120 ].…”