Recent observations from synaptosome preparations have questioned the tetrodotoxin (TTX) insensitivity of nicotine-evoked dopamine release in the striatum, a characteristic previously considered diagnostic of presynaptically located nicotinic acetylcholine receptors (nAChRs). Therefore, we have undertaken a comparison of nicotine-evoked dopamine release in the presence of TTX from the rat striatum in vitro, using synaptosomes and brain slices, and in vivo, using microdialysis. In P2 and Percoll-purified synaptosome preparations, 1.5 mu M TTX partially inhibited nicotine-evoked [H-3]dopamine release by 54% and 37%, respectively, whereas in more intact preparations (brain slices and microdialysis) TTX completely inhibited mecamylamine-sensitive nicotine-stimulated dopamine release. These results suggest that caution should be exercised in the interpretation of TTX sensitivity of nicotine-evoked responses with regard to the location of nAChRs.
- nicotinic acetylcholine receptor (nachr)
- brain slices
- presynaptic receptors
- in vivo microdialysis
Marshall, D., Soliakov, L., Redfern, P., & Wonnacott, S. (1996). Tetrodotoxin-sensitivity of nicotine-evoked dopamine release from rat striatum. Neuropharmacology, 35(11), 1531-1536. https://doi.org/10.1016/S0028-3908(96)00117-7