Sodium channels in transient retinal bipolar cells enhance visual responses in ganglion cells.
Retinal bipolar cells are slow potential neurons that respond to photoreceptor inputs with graded potentials and do not fire action potentials. We found that transient ON bipolar cells recorded in retinal slices possess voltage-gated sodium channels located on either their dendrites or somas. The sodium currents in these neurons did not generate spikes but enhanced voltage responses evoked by visual stimulation, which selectively boosted transmission to transient ganglion cells. In contrast, sodium currents were not found in sustained ON bipolar cells, and light responses in sustained bipolar cells and ganglion cells were not affected by TTX. The presence of sodium channels in transient ON bipolar cells contributed to the separation of transient and sustained signals by selectively enhancing the responses of ON transient ganglion cells to light. Our results suggest that bipolar cell sodium channels augment transient signals and contribute to the temporal segregation of visual information.
Ichinose
Tomomi
T
Department of Ophthalmology and Visual Sciences, Washington University School of Medicine, St. Louis, Missouri 63110, USA.
Shields
Colleen R
CR
Lukasiewicz
Peter D
PD
D000557:Ambystoma / Q000254:growth & development; D000818:Animals; D002794:Choline / Q000494:pharmacology; D003712:Dendrites / Q000502:physiology; D007395:Interneurons / Q000502:physiology* / Q000648:ultrastructure; D015640:Ion Channel Gating; D007814:Larva; D008012:Lidocaine / Q000031:analogs & derivatives / Q000494:pharmacology; D018408:Patch-Clamp Techniques; D010775:Photic Stimulation; D020419:Photoreceptor Cells, Vertebrate / Q000502:physiology; D012165:Retinal Ganglion Cells / Q000502:physiology* / Q000648:ultrastructure; D012964:Sodium / Q000378:metabolism; D026941:Sodium Channel Blockers / Q000494:pharmacology; D015222:Sodium Channels / Q000187:drug effects / Q000502:physiology*; D013779:Tetrodotoxin / Q000494:pharmacology; D013997:Time Factors; D014795:Visual Pathways / Q000502:physiology*
D026941:Sodium Channel Blockers; D015222:Sodium Channels; C012647:QX-314; D013779:Tetrodotoxin; D008012:Lidocaine; D012964:Sodium; D002794:Choline
Nat Neurosci. 1998 Dec;1(8):714-9
10196588
J Neurophysiol. 2000 Apr;83(4):1817-29
10758094
J Neurosci. 2000 Jun 15;20(12):4462-70
10844015
J Neurosci. 2000 Jun 15;20(12):4471-9
10844016
J Neurosci. 2000 Sep 15;20(18):7087-95
10995856
J Neurophysiol. 2000 Nov;84(5):2564-71
11067998
Nature. 2001 Mar 29;410(6828):583-7
11279496
J Neurosci. 2001 Jul 1;21(13):4543-50
11425883
J Neurosci. 2001 Jul 1;21(13):4852-63
11425912
J Neurophysiol. 2001 Oct;86(4):1671-84
11600631
J Neurosci. 2002 Apr 15;22(8):3285-92
11943830
Jpn J Pharmacol. 2002 Apr;88(4):365-77
12046980
Neuroscience. 2002;115(1):163-72
12401331
J Neurophysiol. 2003 May;89(5):2449-58
12611993
J Physiol. 1953 Apr 28;120(1-2):171-204
13062231
J Neurophysiol. 1985 Jan;53(1):153-70
2579215
J Neurophysiol. 1988 Sep;60(3):1122-42
3171660
J Neurosci. 1988 Dec;8(12):4470-81
3199187
Proc Natl Acad Sci U S A. 1986 Mar;83(5):1509-12
3456599
J Neurophysiol. 1969 May;32(3):339-55
4306897
J Gen Physiol. 1974 Jan;63(1):88-110
4359065
J Neurophysiol. 1978 Mar;41(2):472-83
650277
J Physiol. 1978 May;278:79-99
671342
Vision Res. 1982;22(2):257-60
7101761
Neuron. 1995 Nov;15(5):1065-76
7576650
Neurosci Lett. 1995 Apr 14;189(2):109-12
7609913
Pflugers Arch. 1993 Feb;422(5):481-91
7682688
Science. 1995 Apr 14;268(5208):301-4
7716525
J Neurosci. 1994 Jun;14(6):3852-61
7911519
J Neurophysiol. 1994 Jun;71(6):2562-5
7931536
Nature. 1994 Jan 6;367(6458):69-72
8107777
J Neurosci. 1994 Mar;14(3 Pt 1):1202-12
8120620
J Neurosci. 1993 Feb;13(2):660-73
8381170
J Physiol. 1977 Jan;264(3):767-85
845823
J Neurophysiol. 1995 Nov;74(5):2220-4
8592214
J Neurophysiol. 1997 Nov;78(5):2662-73
9356416
J Neurosci. 1998 Mar 15;18(6):2301-8
9482814
J Physiol. 1999 Jan 15;514 ( Pt 2):343-50
9852318