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Evidence that L-AP5 and D,L-AP4 can preferentially block cone signals in the rat retina

Published online by Cambridge University Press:  11 April 2007

DANIEL G. GREEN  and
NATALIA V. KAPOUSTA-BRUNEAU
DANIEL G. GREEN
Affiliation:
Department of Ophthalmology and Visual Sciences, University of Michigan, Ann Arbor, Michigan
NATALIA V. KAPOUSTA-BRUNEAU
Affiliation:
Department of Ophthalmology and Visual Sciences, University of Michigan, Ann Arbor, Michigan
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Abstract

Several lines of evidence suggest that, as concentrations of two agonists of group III metabotropic glutamate receptors are increased, cone contributions to the b-wave are blocked before rod contributions. Application of L-AP5 (L-2-amino-5-phosphonobutyric acid) at concentrations of 50 μM and D,L-AP4 (D,L-2-amino-4-phosphonobutyric acid) at concentrations 2 μM had a greater effect in reducing the amplitude of the rat ERG b-wave at high light intensities than at low light intensities. The amplitude reduction occurs at flash intensities that saturate rod photoreceptor responses. When steady backgrounds are used to saturate rod photoreceptors, the b-wave responses show increased long-wavelength sensitivity. Responses on a rod saturating background are blocked by adding L-AP5 or AP4 at the above concentrations to the perfusate. Further evidence for metabotrophic receptors being involved comes from the observation that even when ionotropic glutamate receptors are pharmacologically blocked with MK801 and DNQX, AP4 selectively blocks cone contributions to the b-wave. Thus we suggest that the type III metabotrophic receptors on depolarizing cone bipolar cells or cone synaptic terminals are affected by concentrations of L-AP5 and D,L-AP4 that have minimal effects on rod bipolar cells or rod synaptic terminals.

Keywords

Cone b-waveIsolated rat retina ERGRod-saturationSelective blockade of cones with L-AP5 and D,L-AP-4
Type
Research Article
Information
Visual Neuroscience , Volume 24 , Issue 1 , January 2007 , pp. 9 - 15
Copyright
© 2007 Cambridge University Press

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References

REFERENCES

Akula, J.D., Lyubarsky, A.L. & Naarendorp, F. (2003). The sensitivity and spectral identity of the cones driving the b-wave of the rat electroretinogram. Visual Neuroscience 20, 109–117.Google Scholar
Coleman, P.A. & Miller, R.F. (1988). Do N-methyl-D-aspartate receptors mediate synaptic responses in the mudpuppy retina? Journal of Neuroscience 8, 4728–4733.Google Scholar
Cone, R.A. (1963). Quantum relations of the rat electroretinogram. Journal of General Physiology 46, 1267–1286.Google Scholar
Dodt, E. & Echter, K. (1961). Dark and light adaptation in pigmented and white rat as measured by electroretinogram threshold. Journal of Neurophysiology 24, 427–445.Google Scholar
Euler, T. & Wässle, H. (1995). Immunocytochemical identification of cone bipolar cells in the rat retina. Journal of Comparative Neurology 361, 461–478.Google Scholar
Green, D.G. (1971). Light adaptation in the rat retina: Evidence for two receptor mechanisms. Science 174, 598–600.Google Scholar
Green, D.G. (1973). Scotopic and photopic components of the rat electroretinogram. Journal of Physiology 228, 781–797.Google Scholar
Green, D.G., Herreros de Tejada, P. & Glover, M.J. (1991). Are albino rats night blind? Investigative Ophthalmology and Visual Science 32, 2366–2371.Google Scholar
Green, D.G. & Kapousta-Bruneau, N.V. (1999a). Electrophysiological properties of a new isolated retina preparation. Vision Research 39, 2165–2177.Google Scholar
Green, D.G. & Kapousta-Bruneau, N.V. (1999b). A dissection of the ERG from the isolated rat retina with microelectrodes and drugs. Visual Neuroscience 16, 727–741.Google Scholar
Hagins, W.A., Penn, R.D. & Yoshikami, S. (1970). Dark current and photocurrent in retinal rods. Biophysical Journal 10, 380–412.Google Scholar
Hirasawa, H., Shiells, R. & Yamada, M. (2002). A metabotropic glutamate receptor regulates transmitter release from cone presynaptic terminals in carp retinal slices. Journal of General Physiology 119, 55–68.Google Scholar
Hosoi, N., Arai, I. & Tachibana, M. (2005). Group III metabotropic glutamate receptors and exocytosed protons inhibit L-type calcium currents in cones but not in rods. Journal of Neuroscience 25, 4062–4072.Google Scholar
Kapousta-Bruneau, N.V. (1999). Effects of sodium pentobarbital on the components of electroretinogram in the isolated rat retina. Vision Research 39, 3498–3512.Google Scholar
Kapousta-Bruneau, N.V. (2000). Opposite effects of GABA(A) and GABA(C) receptor antagonists on the b-wave of ERG recorded from the isolated rat retina. Vision Research 40, 1653–1665.Google Scholar
Kim, H.G. & Miller, R.F. (1991). Rods and cones activate different excitatory amino acid receptors on the mudpuppy retinal horizontal cell. Brain Research 538, 141–146.Google Scholar
Koulen, P., Kuhn, R., Wässle, H. & Brandstatter, J.H. (1999). Modulation of the intracellular calcium concentration in photoreceptor terminals by a presynaptic metabotropic glutamate receptor. Proceedings of the National Academy of Sciences 96, 9909–9914.Google Scholar
Koulen, P. & Brandstatter, J.H. (2002). Pre- and Postsynaptic Sites of Action of mGluR8a in the mammalian retina. Investigative Ophthalmology and Visual Science 43, 1933–1940.Google Scholar
Massey, S.C. & Miller, R.F. (1990). N-methyl-D-aspartate receptors of ganglion cells in rabbit retina. Journal of Neurophysiology 63, 16–30.Google Scholar
Nawy, S., Sie, A. & Copenhagen, D.R. (1989). The glutamate analog 2-amino-4-phosphonobutyrate antagonizes synaptic transmission from cones to horizontal cells in the goldfish retina. Proceedings of the National Academy of Sciences 86, 1726–1730.Google Scholar
Penn, R.D. & Hagins, W.A. (1972). Kinetics of the photocurrent of retinal rods. Biophysical Journal 12, 1073–1094.Google Scholar
Saugstad, J.A., Kinzie, J.M., Shinohara, M.M., Segerson, T.P. & Westbrook, G.L. (1997). Cloning and expression of rat metabotropic glutamate receptor 8 reveals a distinct pharmacological profile. Molecular Pharmacology 51, 119–125.Google Scholar
Thoreson, W.B. & Ulphani, J.S. (1995). Pharmacology of selective and non-selective metabotropic glutamate receptor agonists at L-AP4 receptors in retinal ON bipolar cells. Brain Research 676, 93–102.Google Scholar
Winkler, B.S., Kapousta-Bruneau, N., Arnold, M.J. & Green, D.G. (1999). Effects of inhibiting glutamine synthetase and blocking glutamate uptake on b-wave generation in the isolated rat retina. Visual Neuroscience 16, 345–353.Google Scholar