Purchase this article with an account.
F Huppe-Gourgues, G Coude, C Casanova; Dopaminergic Modulation of the Retinal Function in Rabbit . Invest. Ophthalmol. Vis. Sci. 2002;43(13):3788.
Download citation file:
© ARVO (1962-2015); The Authors (2016-present)
Purpose: Dopamine (DA) is a major neurotransmitters in the retina. DA have different effect on cells depending on which receptor family (D1 or D2) is activated. It has been shown that apomorphine (a mixed D1/D2 receptor agonist) reduces the amplitude of the electroretinogram (ERG) b-wave (Jagadeshh & Sanchez 1981). As part of a project aiming to better understand the role of DA in visual function, we investigated the effects of D1 and D2 ligands on the b-wave amplitude and implicit time in anaesthetised rabbits. Methods: ERGs (1-1000hz) and oscillatory potentials (OPs) (100-300hz) were recorded in scotopic, mesopic and photopic conditions (in respect to ISCEV standard) with Jet-type electrodes. SKF38393 (partial D1 receptor agonist), A77636 (specific D1 receptor agonist) and Norpropylapomorphine (NPA) (D2 receptor agonist) solution were injected intraocularly at various concentrations (100µl). The same procedure was used to inject SCH23390 (D1 antagonist) and Sulpiride (D2 antagonist). The controlateral eye received an injection of the vehicle only. ERG variables were compared between tested and controlled eye. Results: SKF38393 reduced (average : 62%) the amplitude of the b-wave without affecting other components. The maximum effect was seen 2 hours post-injection (t = -3.12, p = 0.005) and a total recovery occurred after ten hours. A77636 also reduced the amplitude of b-wave (28%) but the effect was maximal only ten hours after injection. No recovery of the ERG was observed after 24 hours. Despite the use of ranging from concentration 0.0001 to 1 mg/100µl, NPA failed to significantly modify the b-wave amplitude. The antagonist SCH23390 reduced the amplitude of b-wave (71%, t = -3.47, p = 0.018) as well as Sulpiride 40% but the latter had a longer time course (4 to 6 hours post injection, recovery after 20 hours) compared to 3 hours for SCH23390. Conclusion: Our results suggest that the DA modulation of the b-wave rely on the activation of D1 receptors. Sulpiride may act on the autoreceptors to reduce the amount of released endogenous DA. Supp.: C.C. : CRSNG; F.H.G : FRSQ-FCAR Sante, G.C. : Baker Foundation
This PDF is available to Subscribers Only