Open AccessDL-2-amino-4-phosphonobutyric acid does not eliminate "ON" responses in the visual system of goldfish.
Author(s) -
Paul J. DeMarco,
Joseph Bilotta,
Maureen K. Powers
Publication year - 1991
Publication title -
proceedings of the national academy of sciences of the united states of america
Language(s) - English
Resource type - Journals
eISSN - 1091-6490
pISSN - 0027-8424
DOI - 10.1073/pnas.88.9.3787
Subject(s) - optic nerve , carassius auratus , biology , retinal , optic tectum , electrophysiology , neuroscience , retina , electroretinography , central nervous system , anatomy , biophysics , endocrinology , chemistry , medicine , biochemistry , fish <actinopterygii> , fishery
DL-2-Amino-4-phosphonobutyric acid (APB) suppresses activity in retinal ON pathways. It is generally assumed that loss of the ON pathway would result in loss of ON responses in the visual system. We tested this assumption by recording activity from the optic nerves of intact goldfish (Carassius auratus) before and after intraocular injection of APB. Whole-nerve responses to increments and decrements of light were compared to electroretinogram responses and to tectal evoked potentials. APB severely reduced the amplitude of the electroretinogram b-wave but left ON and OFF responses from the optic nerve and tectum intact, although decreased in sensitivity. We conclude that APB does not completely eliminate ON responses in the visual system, at least in goldfish. The selectivity and effectiveness of APB must be evaluated in other species before this agent can be relied upon as a useful tool in understanding the roles of ON and OFF pathways in visual function.