Effects of forskolin on endogenous dopamine and acetylcholine release in rat neostriatal slices
- 36 Downloads
The involvement of the cyclic AMP (cAMP) effector system in the release of endogenous dopamine and acetylcholine from the rat neostriatum was assessed. Forskolin, an activator of adenylate cyclase, was used to enhance cAMP production, and the consequence of this enhancement on the spontaneous and potassium stimulated release of dopamine and a-cetylcholine was evaluated. Neostriatal slices were prepared from Fischer 344 rats and after a preincubation period the release of each endogenous neurotransmitter was measured from the same slice preparation. To measure acetylcholine release the slice acetylcholinesterase (AChE) activity was inhibited with physostigmine, but the release from slices with intact AChE activity was also determined (choline, instead of acetylcholine was detected in the medium). Under both conditions forskolin induced a significant dose-dependent increase in the potassium-evoked release of dopamine. In the same tissue preparations the release of neither acetylcholine (AChE inhibited) nor choline (AChE intact) was affected by forskolin. The results indicate that the cAMP second messenger system might be involved in neuronal mechanisms that enhance neostriatal dopamine release, but stimulation of this second messenger by forskolin does not further enhance neostriatal acetylcholine release.
Key wordscAMP effector system Forskolin Acetylcholine Dopamine Endogenous release Neostriatal slices
Unable to display preview. Download preview PDF.
- Dryden, W. F., Singh, Y. N., Gordon, T. and Lazarenko, G., Pharmacological elevation of cAMP and transmitter release at the mouse neuromuscular junction.Can. J. Physiol. Pharmacol., 66, 207–212 (1987).Google Scholar
- McIlwain, H. and Rodnight, R., Preparing neural tissues for metabolic studyin vitro. In McIlwain, H. (Eds.),Practical Neurochemistry, Churchill, London, pp. 109–188, 1962.Google Scholar
- Patrick, R. L. and Barchas, J. D., Dopamine synthesis in rat brain striatal synaptosomes. II. Dibutyryl cyclic adenosine 3′∶5′-monophosphoric acid and 6-methyltetrahydropteridine-induced synthesis increase without an increase in endogenous dopamine release.J. Pharmacol. Exp. Ther. 197, 97–104 (1976).PubMedGoogle Scholar
- Weiler, M. H., Muscarinic modulation of endogenous acetylcholine release in rat neostriatal slices. J. Pharm. Exp. Ther. 250, 617–623 (1989).Google Scholar