[Modulation of tracer coupling in AII amacrine cells and ON cone bipolars of rabbit retina by L-arginine].
OBJECTIVE
To determine the relative permeability of the gap junction pathways in AII amacrine cells and ON cone bipolar cells of rabbit retina, and its modulation by L-arginine.


METHODS
The distribution of neurobiotin across the heterologous cell assembly was measured using the confocal microscope after microinjecting neurobiotin into a single AII amacrine cell. Modulation of the tracer coupling by 4 mmol/L L-arginine was also observed. Rabbit anti-calretinin antibody was used to stain the retina injected with neurobiotin.


RESULTS
Average neurobiotin concentration in the coupled ON cone bipolar cells was lower than that in the coupled AII amacrine cells. L-arginine selectively reduced the concentration of neurobiotin in the ON cone bipolar cells, this effect was more prominent than that observed in the AII amacrine cells (P < 0.05). AII amacrine cells stained with anti-calretinin antibody.


CONCLUSIONS
Neurobiotin can pass easily through homologous AII/AII cells gap junctions as compared to the heterologous AII/bipolar cells gap junctions. L-arginine reduces the labeling of neurobiotin in ON cone bipolar cells to a greater degree than in AII amacrine cells. The pathway of this effect is probably by increasing the level of cGMP and acting at the bipolar cell side of this gap junction.
Xia
Xiao-bo
XB
Department of Ophthalmology, Xiangya Hospital of Central South University, Changsha 410008, China. xbxia@yahoo.com
Mills
Stephen L
SL
Huang
Pei-gang
PG
Jiang
You-qin
YQ
D025042:Amacrine Cells / Q000166:cytology / Q000187:drug effects*; D000818:Animals; D001120:Arginine / Q000494:pharmacology*; D002478:Cells, Cultured; D005260:Female; D017629:Gap Junctions / Q000502:physiology*; D008297:Male; D011817:Rabbits; D017949:Retinal Cone Photoreceptor Cells / Q000166:cytology / Q000187:drug effects*
D001120:Arginine