Dopaminergic regulation of cone retinomotor movement in isolated teleost retinas: I. Induction of cone contraction is mediated by D2 receptors.

摘要: In the retinas of lower vertebrates, retinal photoreceptors and melanin pigment granules epithelium (RPE) undergo characteristic movements in response to changes light intensity signals from an endogenous circadian clock. To identify agents responsible for mediating and/or regulation these retinomotor movements, we investigated effects hormones neurotransmitters on cone, rod, RPE green sunfish, Lepomis cyanellus. We report here that 3,4-dihydroxyphenylethylamine (dopamine) mimics effect by inducing light-adaptive all three cell types. isolated dark-cultured retinas, dopamine induced cone contraction with a half-maximal at 10(-8) M. This was inhibited antagonists potency order D2 receptor mediation. The uptake blocker benztropine also suggesting there is continuous release dark but concomitant normally prevents activation contraction. That plays role movement further suggested observation light-induced partially sulpiride, selective antagonist, or Co2+, synaptic transmission. Sulpiride promoted dark-adaptive elongation light-adapted action required maintain position. Dopamine can act directly receptors located rod inner/outer segments: distal fragments dark-adapted cultured dark. Together our results indicate induces cones, rods, cells activating receptors. suggest that, vivo, both movements.