JN Miami Valley Hospital
HOME HELP FEEDBACK SUBSCRIPTIONS ARCHIVE SEARCH
 QUICK SEARCH:   [advanced]


     


J Neurophysiol (December 15, 2004). doi:10.1152/jn.00839.2004
This Article
Right arrow Full Text (PDF)
Right arrow All Versions of this Article:
93/6/3479    most recent
00839.2004v1
Right arrow Alert me when this article is cited
Right arrow Alert me if a correction is posted
Services
Right arrow Email this article to a friend
Right arrow Similar articles in this journal
Right arrow Similar articles in PubMed
Right arrow Alert me to new issues of the journal
Right arrow Download to citation manager
Citing Articles
Right arrow Citing Articles via HighWire
Right arrow Citing Articles via Google Scholar
Google Scholar
Right arrow Articles by Protti, D. A.
Right arrow Articles by Waessle, H.
Right arrow Search for Related Content
PubMed
Right arrow PubMed Citation
Right arrow Articles by Protti, D. A.
Right arrow Articles by Waessle, H.
Submitted on August 16, 2004
Accepted on December 7, 2004

Light signaling in scotopic conditions in the rabbit, mouse and rat retina: a physiological and anatomical study

Dario A. Protti*, Nicolas Flores-Herr, Wei Li, Stephen C. Massey, and Heinz Waessle

* To whom correspondence should be addressed. E-mail: dariop{at}physiol.usyd.edu.au.

In the dark, light signals are conventionally routed through the following circuit: rods synapse onto rod bipolar (RB) cells, which in turn contact AII amacrine cells. AII cells segregate the light signal into the ON and OFF pathways by making electrical synapses with ON cone bipolar (CB) cells and glycinergic inhibitory chemical synapses with OFF CB cells. These bipolar cells then synapse onto their respective ganglion cells, which transfer ON and OFF signals to the visual centers of the brain. Two alternative pathways have recently been postulated for the signal transfer in scotopic conditions: 1) electrical coupling between rods and cones, and 2) a circuit independent of cone photoreceptors, implying direct contacts between rods and OFF-CB cells. Anatomical evidence supports the existence of both these circuits. To investigate the contribution of these alternative pathways to scotopic vision in the mammalian retina, we have performed patch-clamp recordings from ganglion cells in the dark adapted retina of the rabbit, mouse and rat. Approximately half of the ganglion cells in the rabbit retina received OFF signals through a circuit that was independent of RB cells. This was shown by their persistence in the presence of the glutamate agonist 2-amino-4-phosphonobutyric acid (APB), which blocks rod to RB cell signalling. Consistent with this result, strychnine, a glycine receptor antagonist, was unable to abolish these OFF responses. In addition, we were able to show that some OFF cone bipolar dendrites terminate at rod spherules and make potential contacts. In the mouse retina, however, there seems to be a very low proportion of OFF signals carried by an APB resistant pathway. No ganglion cells in the rat retina displayed APB- and strychnine resistant responses. Our data support signaling through flat contacts between rods and OFF-CB cells as the alternative route, but suggest that the significance of this pathway differs between species.




This article has been cited by other articles:


Home page
J. Physiol.Home page
D. K. Mojumder, D. M. Sherry, and L. J. Frishman
Contribution of voltage-gated sodium channels to the b-wave of the mammalian flash electroretinogram
J. Physiol., May 15, 2008; 586(10): 2551 - 2580.
[Abstract] [Full Text] [PDF]


Home page
J. Physiol.Home page
E. D. Eggers, M. A. McCall, and P. D. Lukasiewicz
Presynaptic inhibition differentially shapes transmission in distinct circuits in the mouse retina
J. Physiol., July 15, 2007; 582(2): 569 - 582.
[Abstract] [Full Text] [PDF]


Home page
J. Neurosci.Home page
D. J. Margolis and P. B. Detwiler
Different Mechanisms Generate Maintained Activity in ON and OFF Retinal Ganglion Cells
J. Neurosci., May 30, 2007; 27(22): 5994 - 6005.
[Abstract] [Full Text] [PDF]


Home page
J. Neurosci.Home page
D.-Q. Zhang, T.-R. Zhou, and D. G. McMahon
Functional Heterogeneity of Retinal Dopaminergic Neurons Underlying Their Multiple Roles in Vision
J. Neurosci., January 17, 2007; 27(3): 692 - 699.
[Abstract] [Full Text] [PDF]


Home page
J. Neurosci.Home page
S. Haverkamp, S. Michalakis, E. Claes, M. W. Seeliger, P. Humphries, M. Biel, and A. Feigenspan
Synaptic plasticity in CNGA3(-/-) mice: cone bipolar cells react on the missing cone input and form ectopic synapses with rods.
J. Neurosci., May 10, 2006; 26(19): 5248 - 5255.
[Abstract] [Full Text] [PDF]




HOME HELP FEEDBACK SUBSCRIPTIONS ARCHIVE SEARCH
Visit Other APS Journals Online
Copyright © 2004 by the The American Physiological Society.