HOME HELP FEEDBACK SUBSCRIPTIONS ARCHIVE SEARCH TABLE OF CONTENTS		QUICK SEARCH:   [advanced] Author: Keyword(s): Year:  Vol:  Page:

This Article Full Text (PDF) Services Email this article to a friend Similar articles in this journal Similar articles in PubMed Alert me to new issues of the journal Download to citation manager Citing Articles Citing Articles via HighWire Citing Articles via Google Scholar Google Scholar Articles by Lamb, T D Search for Related Content PubMed PubMed Citation Articles by Lamb, T D

Rod current responses were measured over the range 5-30 degrees C. Following a rapid decrease in temperature the amplitude of the dark current decreased without detectable delay (less than 3 s). Over a period of several minutes the amplitude of the dark current sometimes relaxed slightly towards its previous value. The rapid change cannot be accounted for simply by altered activity of the sodium pump and instead indicates that the conductance of the outer segment in darkness changes with temperature. Over the range 10-30 degrees C the amplitude of the dark current increased approximately linearly with temperature, and the straight line of best fit extrapolated to zero current at about 5 degrees C. The few points available below 10 degrees C indicated that the relationship flattened out, but this could not be investigated properly. The kinetics of responses to dim flashes accelerated with a Q10 of about 2.2, and were well described by an Arrhenius plot with an activation energy of 13.8 kcal mol-1 (HEPES Ringer solution). The time course of recovery of dark current following a saturating flash showed a similar temperature dependence to that of the dim flash kinetics. A simple explanation of the previous two findings is that the delays determining the time course of responses to both dim and bright flashes are largely determined by the fluidity of the disk membrane. The sensitivity to dim flashes had a broad peak at about 22 degrees C, decreasing at both lower and higher temperatures. The relative sensitivity to long wave-length light increased slightly with temperature. The sensitivity at 700 nm relative to that at 500 nm increased by 0.225 log10 units (1.68 times) upon a temperature increase from 11.5 to 29.3 degrees C (from approximately -5.0 log10 units to approximately -4.8 log10 units). This change appears to be approximately what would be expected theoretically.

This article has been cited by other articles:

				A. Knopp and H. Ruppel Calcium-Sensitive Downregulation of the Transduction Chain in Rod Photoreceptors of the Rat Retina Biophys. J., August 1, 2006; 91(3): 1078 - 1089. [Abstract] [Full Text] [PDF]

				S Nymark, H Heikkinen, C Haldin, K Donner, and A Koskelainen Light responses and light adaptation in rat retinal rods at different temperatures J. Physiol., September 15, 2005; 567(3): 923 - 938. [Abstract] [Full Text] [PDF]

				B. Falsini, F. Focosi, F. Molle, C. Manganelli, G. Iarossi, A. Fadda, G. Dorin, and M. A. Mainster Monitoring Retinal Function during Transpupillary Thermotherapy for Occult Choroidal Neovascularization in Age-Related Macular Degeneration Invest. Ophthalmol. Vis. Sci., May 1, 2003; 44(5): 2133 - 2140. [Abstract] [Full Text] [PDF]

				N. K. Dhingra, Y.-H. Kao, P. Sterling, and R. G. Smith Contrast Threshold of a Brisk-Transient Ganglion Cell In Vitro J Neurophysiol, May 1, 2003; 89(5): 2360 - 2369. [Abstract] [Full Text] [PDF]

				S. E. Brockerhoff, F. Rieke, H. R. Matthews, M. R. Taylor, B. Kennedy, I. Ankoudinova, G. A. Niemi, C. L. Tucker, M. Xiao, M. C. Cilluffo, et al. Light Stimulates a Transducin-Independent Increase of Cytoplasmic Ca2+ and Suppression of Current in Cones from the Zebrafish Mutant nof J. Neurosci., January 15, 2003; 23(2): 470 - 480. [Abstract] [Full Text] [PDF]

				A. P. Sampath and D. A. Baylor Molecular Mechanism of Spontaneous Pigment Activation in Retinal Cones Biophys. J., July 1, 2002; 83(1): 184 - 193. [Abstract] [Full Text] [PDF]