Modulation of horizontal cell function by dopaminergic ligands in mammalian retina.
Light responses of rabbit horizontal cell somata (HC) to flickering light stimuli recorded with sharp electrodes consist of a distinctive flicker component superimposed on a sustained hyperpolarisation. Activation of dopamine D1/D5 receptors depolarises HC dark membrane potential and suppresses the flicker component of responses to photopic stimuli without affecting the sustained hyperpolarising response component. Waveforms of responses to scotopic stimuli are preserved. Similar response modulation was observed in depolarising cells of the inner retina, suggesting that activation of D1/D5 receptors of HC causes modification of cone signal transmission to higher order neurons. The impact of dopamine D1/D5 receptor activation on the function of HC in the light stimulated retina is discussed.
Pflug
Renate
R
Center for Physiology and Pathophysiology, Department of Physiology, Medical University of Vienna, Schwarzspanierstrasse 17, 1090 Vienna, Austria. renate.pflug@meduniwien.ac.at <renate.pflug@meduniwien.ac.at>
Nelson
Ralph
R
Huber
Sonja
S
Reitsamer
Herbert
H
D015647:2,3,4,5-Tetrahydro-7,8-dihydroxy-1-phenyl-1H-3-benzazepine / Q000494:pharmacology; D000818:Animals; D001058:Apomorphine / Q000494:pharmacology; D003623:Dark Adaptation; D004298:Dopamine / Q000494:pharmacology*; D018491:Dopamine Agonists / Q000494:pharmacology; D025461:Feedback, Physiological; D008322:Mammals / Q000502:physiology*; D008564:Membrane Potentials / Q000187:drug effects; D010775:Photic Stimulation; D019257:Quinpirole / Q000494:pharmacology; D011817:Rabbits; D011954:Receptors, Dopamine / Q000378:metabolism*; D012160:Retina / Q000166:cytology / Q000187:drug effects / Q000378:metabolism*; D017949:Retinal Cone Photoreceptor Cells / Q000187:drug effects; D017948:Retinal Rod Photoreceptor Cells / Q000187:drug effects; D046509:Tissue Culture Techniques
D018491:Dopamine Agonists; D011954:Receptors, Dopamine; D019257:Quinpirole; D015647:2,3,4,5-Tetrahydro-7,8-dihydroxy-1-phenyl-1H-3-benzazepine; D001058:Apomorphine; D004298:Dopamine