The following HTML text is provided to enhance online
readability. Many aspects of typography translate only awkwardly to HTML.
Please use the page image
as the authoritative form to ensure accuracy.
COLLOQUIUM ON VISION: FROM PHOTON TO PERCEPTION
cascade—an amplifying strategy reminiscent of that of the rods themselves (43,44). A glutamate receptor activated by the rod transmitter released in darkness appears to continually activate a G protein and in turn a cGMP PDE, which holds the level of cGMP low in darkness. A light-triggered reduction in the activity of the glutamate receptor allows cGMP levels to rise, opening cationic channels in the surface membrane and producing a depolarization which carries the message onward. It will undoubtedly be satisfying to learn more about how synaptic transmission is “ designed” to work in concert with the visual transduction mechanism. Already it appears that synaptic transmission has borrowed a successful molecular strategy from visual transduction itself.
Drs. Leon Lagnado, Clint Makino, Martha Erickson, and Robert Dodd did much of the recent work reported here, and I acknowledge their contributions with many thanks. Drs. Clint Makino, Martha Erickson, and Fred Rieke made useful comments on the manuscript. This research was supported by Grants EY01543 and EY05750 from the National Eye Institute, National Institutes of Health, as well as grants from the Alcon Research Institute, the Ruth and Milton Steinbach Fund, and the McKnight Foundation. Dr. Lubert Stryer's group is a continuing source of stimulating interactions.
31. Hsu, Y. T. & Molday, R. S. ( 1993) Nature (London)361, 76–79.
32. Gorczyca, W. A., Gray-Keller, M. P., Detwiler, P. B. & Palczewski, K. ( 1994) Proc. Natl. Acad. Sci. USA91, 4014–4018.
33. Palczewski, K., Subbaraya, I., Gorczyca, W. A., Helekar, B. S., Ruiz, C. C., Ohguro, H., Huang, J., Zhao, X., Crabb, J. W., Johnson, R. S., Walsh, K. A., Gray-Keller, M. P., Detwiler, P. B. & Baehr, W. ( 1994) Neuron13, 395–404.
34. Dizhoor, A. M., Lowe, D. G., Olshevskaya, E. V., Laura, R. P. & Hurley, J. B. ( 1994) Neuron12, 1345–1352.
35. Kawamura, S. ( 1993) Nature (London)362, 855–857.
36. Koutalos, Y. & Yau, K.-W. ( 1995) J. Gen. Physiol.106, 891–921.
37. Gray-Keller, M. P., Polans, A. S., Palczewski, K. & Detwiler, P. B. ( 1993) Neuron10, 523–531.
38. Baylor, D. A., Lamb, T. D. & Yau, K.-W. ( 1979) J. Physiol. (London)288, 613–634.
39. Lyubarsky, A. L., Nikonov, S. S. & Pugh, E. N. ( 1995) Invest. Ophthalmol. Visual Sci.36, S277.
40. Pepperberg, D. R., Cornwall, M. C., Kahlert, M., Hofmann, K. P., Jin, J., Jones, G. J. & Ripps, H. ( 1992) Visual Neurosci.8, 9–18.
41. Corson, D. W., Cornwall, M. C. & Pepperberg, D. R. ( 1994) Visual Neurosci.11, 91–98.
42. Gray, E. G. & Pease, H. L. ( 1971) Brain Res.35, 1–15.
43. Nawy, S. & Jahr, C. E. ( 1990) Nature (London)346, 269–271.
44. Shiells, R. A. and Falk, G. ( 1990) Proc. R. Soc. London B242, 91–94.