Dopaminergic modulation of horizontal-cell-axon-terminal receptive field size in the mammalian retina.
Receptive fields of gap junction-coupled axon terminals of B-type horizontal cells of isolated rabbit retinae were measured by recording light responses to slit shaped light stimuli at different eccentricities from the recording site. The D1/D5 agonist SKF-38393 and the membrane permeant second messenger 8-bromo-cAMP caused decreases of space constants by 20% while the D1/D5 antagonist SCH-23390 increased space constants by 25%. The results of this study indicate that axon terminal receptive fields of the rabbit retina can be modulated by D1/D5 receptor activation based on a cAMP-mediated mechanism. The data also suggest the presence of endogenous dopamine as an agent for axon terminal receptive field size modulation.
Reitsamer
Herbert A
HA
Department of Physiology, Center for Physiology and Pathophysiology, Medical University of Vienna, Austria.
Pflug
Renate
R
Franz
Melchior
M
Huber
Sonja
S
D015647:2,3,4,5-Tetrahydro-7,8-dihydroxy-1-phenyl-1H-3-benzazepine / Q000494:pharmacology; D000818:Animals; D004298:Dopamine / Q000502:physiology*; D018491:Dopamine Agonists / Q000494:pharmacology; D005260:Female; D017629:Gap Junctions / Q000502:physiology; D008297:Male; D010775:Photic Stimulation / Q000379:methods; D017729:Presynaptic Terminals / Q000502:physiology* / Q000648:ultrastructure; D011817:Rabbits; D017447:Receptors, Dopamine D1 / Q000502:physiology; D050641:Receptors, Dopamine D5 / Q000502:physiology; D012160:Retina / Q000502:physiology*; D014794:Visual Fields / Q000187:drug effects / Q000502:physiology*
D018491:Dopamine Agonists; D017447:Receptors, Dopamine D1; D050641:Receptors, Dopamine D5; D015647:2,3,4,5-Tetrahydro-7,8-dihydroxy-1-phenyl-1H-3-benzazepine; D004298:Dopamine