Medical College of Wisconsin
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The "ON"-bipolar agonist, L-2-amino-4-phosphonobutyrate, blocks light-evoked cone contraction in xenopus eye cups. Neurochem Res 1992 Jan;17(1):75-80 PMID: 1538827

Pubmed ID



Rhythmic photoreceptor metabolism in relationship to light-dark cycles is now thought to be regulated through a retinal feed-back mechanism with dopamine serving as a principal signal initiating light-evoked events. In order to test the hypothesis that depolarizing "ON"-bipolar neurons participate in the retinal signalling pathway, we determined the effects of L-2-amino-4-phosphonobutyrate (L-APB) on light-evoked cone contraction in eye cups from Xenopus laevis. L-APB blocked the response stereospecifically when applied over a broad concentration range. The high specificity of L-APB in retina suggests that sign-inverting bipolar neurons which depolarize in light are in the signalling pathway. One possibility is that this pathway conveys signals that regulate dopamine release.

Author List

Besharse JC


Joseph C. Besharse PhD Director, Professor in the Ophthalmology and Visual Sciences department at Medical College of Wisconsin


2-s2.0-0026555065   16 Citations

MESH terms used to index this publication - Major topics in bold

Dopamine Antagonists
Photoreceptor Cells
Signal Transduction
Xenopus laevis
jenkins-FCD Prod-353 9ccd8489072cb19f5b9f808bb23ed672c582f41e