Abstract
The retina is an area of the central nervous system that possesses intrinsic cholinergic neurones which release acetylcholine (ACh) in response to stimulation with flickering light. Using an eye-cup preparation in anaesthetized rabbits we found that when the retina was exposed to the P2-purinoceptor antagonist, PPADS, the light-evoked release of ACh was strikingly increased (by over 40%). In contrast, ATP reduced the light-evoked release of ACh by 20%. The inhibitory effect of ATP was not due to its catabolism to adenosine because it was not affected by the A1-adenosine receptor antagonist, DPCPX, in combination with adenosine deaminase. The actions of both ATP and PPADS were completely blocked by strychnine. We conclude that during physiological stimulation of the retina with light, ATP is co-released with ACh and partially inhibits ACh release by activating (with ACh) an inhibitory glycinergic feedback loop.
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- Blazynski C. Displaced cholinergic, GABAergic amacrine cells in the rabbit retina also contain adenosine. Vis Neurosci. 1989 Nov;3(5):425–431. doi: 10.1017/s0952523800005927. [DOI] [PubMed] [Google Scholar]
- Blazynski C., Woods C., Mathews G. C. Evidence for the action of endogenous adenosine in the rabbit retina: modulation of the light-evoked release of acetylcholine. J Neurochem. 1992 Feb;58(2):761–767. doi: 10.1111/j.1471-4159.1992.tb09783.x. [DOI] [PubMed] [Google Scholar]
- Cunningham J. R., Neal M. J. Effect of excitatory amino acids and analogues on [3H]acetylcholine release from amacrine cells of the rabbit retina. J Physiol. 1985 Sep;366:47–62. doi: 10.1113/jphysiol.1985.sp015784. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Lambrecht G., Friebe T., Grimm U., Windscheif U., Bungardt E., Hildebrandt C., Bäumert H. G., Spatz-Kümbel G., Mutschler E. PPADS, a novel functionally selective antagonist of P2 purinoceptor-mediated responses. Eur J Pharmacol. 1992 Jul 7;217(2-3):217–219. doi: 10.1016/0014-2999(92)90877-7. [DOI] [PubMed] [Google Scholar]
- Perez M. T., Ehinger B. E., Lindström K., Fredholm B. B. Release of endogenous and radioactive purines from the rabbit retina. Brain Res. 1986 Nov 19;398(1):106–112. doi: 10.1016/0006-8993(86)91255-2. [DOI] [PubMed] [Google Scholar]