Abstract.
In the retinae of lower vertebrates, several morphological changes, including photomechanical movements of rods, cones and pigment epithelium, occur during light and dark adaptation. We studied the contribution of exogenous and endogenous circadian control mechanisms to rod retinomotor movements in the teleost retina and their dependence on an intact dopaminergic system. Blue acara (Aequidens pulcher) were kept under a 12:12 h light/dark cycle. One population of fish remained untreated; another population was treated with 6-hydroxy-dopamine, selectively to destroy dopaminergic cells. Rod positions were determined in semi-thin radial sections. During the normal light/dark cycle, rods were elongated during the day and contracted at night. Rod retinomotor movements persisted during two cycles of continuous darkness. Expected light levels of rod positions were reduced by about 40% in comparison with normal light phases. Adaptation-dependent retinomotor movements and movements driven by an endogenous circadian clock also occurred in dopamine-depleted retinae. No statistically significant differences were observed between dopamine-containing and dopamine-depleted retinae. We conclude that rod retinomotor movements in teleost retinae are controlled by light and by an endogenous circadian clock. Dopamine plays no essential role in the light-dependent and endogenous control of rod retinomotor movements.
Similar content being viewed by others
Author information
Authors and Affiliations
Additional information
Received: 19 January 1996 / Accepted: 17 May 1996
Rights and permissions
About this article
Cite this article
Kolbinger, W., Wagner, D. & Wagner, HJ. Control of rod retinomotor movements in teleost retinae: the role of dopamine in mediating light-dependent and circadian signals. Cell Tissue Res 285, 445–451 (1996). https://doi.org/10.1007/s004410050661
Issue Date:
DOI: https://doi.org/10.1007/s004410050661