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Nicotine exerts a permissive role on NMDA receptor function in hippocampal noradrenergic terminals
- Source :
-
Neuropharmacology . Jul2004, Vol. 47 Issue 1, p65-71. 7p. - Publication Year :
- 2004
-
Abstract
- The coexistence of nicotinic cholinergic receptors (nAChRs) and of N-methyl-d-aspartate (NMDA) receptors on the same noradrenergic axon terminals and the nAChR/NMDA receptor cross-talk were investigated by monitoring the release of noradrenaline (NA) evoked in superfused rat hippocampal synaptosomes by (-)-nicotine and NMDA alone or in combination. In medium containing a physiological concentration (1.2 mM) of Mg2+, the release of [3H]NA was very slightly increased by NMDA plus glycine, whereas it was significantly enhanced by (-)-nicotine. The (-)-nicotine/NMDA combination elicited supraadditive release which was totally abolished by the nAChR blocker mecamylamine and partly prevented by selectively blocking NMDA receptors. Supraadditive [3H]NA release was also observed by exposing synaptosomes to veratrine, but not to ionomycin. The supraadditive release elicited by the (-)-nicotine/NMDA or the veratrine/NMDA combination was sensitive to the protein kinase A/C inhibitor staurosporine and the selective protein kinase A inhibitor H89, but insensitive to the protein kinase C inhibitor Ro 31-8220. It is concluded that (i) release-modulating nAChRs and NMDA receptors coexist on hippocampal noradrenergic axon terminals; and (ii) nicotine permits NMDA receptor activation in the presence of Mg2+, possibly because the nicotine-induced influx of Na+ depolarizes the nerve ending membrane sufficiently to remove the Mg2+ block. [Copyright &y& Elsevier]
- Subjects :
- *CHOLINERGIC receptors
*NICOTINE
*PROTEIN kinases
*ANTIHYPERTENSIVE agents
Subjects
Details
- Language :
- English
- ISSN :
- 00283908
- Volume :
- 47
- Issue :
- 1
- Database :
- Academic Search Index
- Journal :
- Neuropharmacology
- Publication Type :
- Academic Journal
- Accession number :
- 13243771
- Full Text :
- https://doi.org/10.1016/j.neuropharm.2004.02.018