Dependence of retinogeniculate transmission in cat on NMDA receptors

Abstract

1. We have examined the possibility that N-methyl-D-aspartate (NMDA) receptors may be involved in the visual response of relay cells in the cat dorsal lateral geniculate nucleus (dLGN). The selective NMDA receptor antagonists D-2-amino-5-phosphonovalerate (APV) and 3-[(+/-)-2-carboxypiperazin-4-yl]-propyl-1-phosphonic acid (CPP) have been iontophoretically applied to X and Y cells in the dLGN and their effects on the visual response to a light spot flashed within the receptive field center determined. 2. The antagonist effects were assessed at ejection current levels producing a selective blockade of the responses to iontophoretically applied NMDA with respect to those elicited by the non-NMDA receptor agonists quisqualate and kainate. These selective effects were determined in an experimental paradigm where the visual response and responses to NMDA and the non-NMDA receptor agonists were compared in the same test run. The data refer to a total population of 52 cells (28 X, 24 Y). 3. Application of APV abolished or greatly reduced the visual responses of both X and Y cells. The mean percentage reduction in the visual response for the X cells studied was 59 +/- 10% (SE; n = 7) and for the Y cells 66 +/- 8% (SE; n = 11). Both the early onset transient and the sustained component of the visual response to the flashed stimulus were equally affected. 4. The antagonist CPP produced a similar pattern of effect to APV, substantially reducing or abolishing the visual response in both X and Y cells.(ABSTRACT TRUNCATED AT 250 WORDS)

Pattern-Dependent Role of NMDA Receptors in Action Potential Generation: Consequences on Extracellular Signal-Regulated Kinase Activation

“…An alternative explanation is that NMDARs could play a critical role in action potential generation and that the stimulation pattern is important in determining how much or how little a role. Supporting this idea is the observation that NMDAR antagonists can inhibit cell firing in the visual system (Miller et al, 1989;Sillito et al, 1990;Blitz and Regehr, 2003) (but see Bear et al, 1990) and in the hippocampus, as assessed by population spike size (Abraham and Mason, 1988;Burgard et al, 1989;Dahl et al, 1990). Here, we show that NMDARs do play a critical role in action potential generation in the hippocampal slice and that this role is dependent on stimulation pattern.…”

“…Previous work has shown that NMDARs can be important in cell firing, both in the visual system (Miller et al, 1989;Sillito et al, 1990;Blitz and Regehr, 2003) and in the dentate gyrus of the hippocampus (Abraham and Mason, 1988;Burgard et al, 1989;Dahl et al, 1990). The consequences of NMDAR inhibition on action potential generation in hippocampal neurons using LTPinducing stimulation, however, have not been studied previously.…”

A Role for Nitric Oxide in the Development of the Ferret Retinogeniculate Projection

“…Postsynaptic NMDA receptors contribute significantly to retinogeniculate synaptic transmission (Sillito et al, 1990;Kwon et al, 1991;Esguerra et al, 1992;Ramoa and McCormick, 1994). NMDA receptor antagonists infused into the ferret LGN disrupt the pattern of sublamination of presynaptic retinogeniculate axons; retinal ganglion cell axon arbors are either abnormally large or are restricted in size but terminate in inappropriate locations within the LGN (Hahm et al, 1991).…”

A Behavioral Analysis of the Spatial Learning Deficit Induced by the NMDA Receptor Antagonist MK-801 (Dizocilpine) in the Rat

“…MK-801 produces a doserelated spectrum of such motor dysfunctions as hyperactivity, stereotypies, or ataxia (Koek et al 1988;Murata and Kawasaki 1993). In addition, NMDA receptor antagonists including MK-801 also affect certain aspects of sensory processing (al-Amin and Schwarzkopf 1996;Cain et al 1997;Sillito et al 1990;Tang and Ho 1988). Therefore, it is essential to determine whether learning and memory deficits caused by MK-801 can be dissociated from nonspecific behavioral effects.…”