کد مقاله | کد نشریه | سال انتشار | مقاله انگلیسی | نسخه تمام متن |
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4320450 | 1290871 | 2006 | 13 صفحه PDF | دانلود رایگان |
![عکس صفحه اول مقاله: Dopamine release in human neocortical slices: Characterization of inhibitory autoreceptors and of nicotinic acetylcholine receptor-evoked release Dopamine release in human neocortical slices: Characterization of inhibitory autoreceptors and of nicotinic acetylcholine receptor-evoked release](/preview/png/4320450.png)
The autoinhibitory control of electrically evoked release of [3H]-dopamine and the properties of that induced by nicotinic receptor (nAChR) stimulation were studied in slices of the human neocortex. In both models [3H]-dopamine release was action potential-induced and exocytotic. The selective dopamine D2 receptor agonist (−)-quinpirole reduced electrically evoked release of [3H]-dopamine, yielding IC50 and Imax values of 23 nM and 76%, respectively. Also, the effects of several other subtype-selective dopamine receptor ligands confirmed that the terminal dopamine autoreceptor belongs to the D2 subtype. The autoinhibitory feedback control was slightly operative under stimulation conditions of 90 pulses and 3 Hz, with a biophase concentration of endogenous dopamine of 3.6 nM, and was enhanced under blockade of dopamine reuptake. [3H]-dopamine release evoked in an identical manner in mouse neocortical slices was not inhibited by (−)-quinpirole, suggesting the absence of dopamine autoreceptors in this tissue and underlining an important species difference.Also, nAChR stimulation-induced release of [3H]-dopamine revealed a species difference: [3H]-dopamine release was evoked in human, but not in rat neocortical slices. The nAChRs inducing [3H]-dopamine release most probably belong to the α3/β2-subtype, according to the potencies and efficacies of subtype-selective nAChR ligands. Part of these receptors may be located on glutamatergic neurons.
Journal: Brain Research Bulletin - Volume 68, Issue 5, 30 January 2006, Pages 361–373