An alternative pathway for signal flow from rod photoreceptors to ganglion cells in mammalian retina.

Abstract

Rod signals in the mammalian retina are thought to reach ganglion cells over the circuit rod-->rod depolarizing bipolar cell-->AII amacrine cell-->cone bipolar cells-->ganglion cells. A possible alternative pathway involves gap junctions linking the rods and cones, the circuit being rod-->cone-->cone bipolar cells-->ganglion cells. It is not clear whether this second pathway indeed relays rod signals to ganglion cells. We studied signal flow in the isolated rabbit retina with a multielectrode array, which allows the activity of many identified ganglion cells to be observed simultaneously while the preparation is stimulated with light and/or exposed to drugs. When transmission between rods and rod depolarizing bipolar cells was blocked by the glutamate agonist 2-amino-4-phosphonobutyric acid (APB), rod input to all On-center and briskly responding Off-center ganglion cells was dramatically reduced as expected. Off responses persisted, however, in Off-center sluggish and On-Off direction-selective ganglion cells. Presumably these responses were generated by the alternative pathway involving rod-cone junctions. This APB-resistant pathway may carry the major rod input to Off-center sluggish and On-Off direction-selective ganglion cells.

• Authors: S H DeVries, D A Baylor
• Journal: Proceedings of the National Academy of Sciences of the United States of America (Proc Natl Acad Sci U S A) Vol. 92 Issue 23 Pg. 10658-62 (Nov 07 1995) ISSN: 0027-8424 [Print] United States
• PMID: 7479860 (Publication Type: Journal Article, Research Support, Non-U.S. Gov't, Research Support, U.S. Gov't, P.H.S.)

Chemical References

• Aminobutyrates
• Excitatory Amino Acid Agonists
• 2-amino-4-phosphonobutyric acid

Topics

• Aminobutyrates (pharmacology)
• Animals
• Cell Communication
• Dose-Response Relationship, Radiation
• Electrophysiology
• Excitatory Amino Acid Agonists (pharmacology)
• In Vitro Techniques
• Light
• Models, Biological
• Rabbits
• Retinal Ganglion Cells (physiology)
• Retinal Rod Photoreceptor Cells (drug effects, physiology, radiation effects)
• Vision, Ocular (physiology)