Modulation of coupling between retinal horizontal cells by retinoic acid and endogenous dopamine

The regulation of electrical coupling between retinal neurons appears to be an important component of the neuronal mechanism of light adaptation, whic h enables the retina to operate efficiently over a broad range of light int ensities. The information about the ambient light conditions has to be tran smitted to the neuronal network of the retina and previous evidence has ind icated that dopamine is an important neurochemical signal. In addition, rec ent studies suggest that another important chemical signal is retinoic acid , which is a light-correlated byproduct of the phototransduction cycle. Thi s review summarizes the latest findings about the effects of dopamine and r etinoic acid on gap junctional coupling in the retinas of mouse, rabbit and fish. (C) 2000 Elsevier Science B.V. All rights reserved.