999 resultados para A7
Resumo:
1894/05/03 (A7,N293)-1894/05/09.
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1894/04/12 (A7,N290)-1894/04/18.
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1894/06/07 (A7,N298)-1894/06/13.
Resumo:
Nicotine (NIC), the main psychostimulant compound of smoked tobacco, exerts its effects through activation of central nicotinic acetylcholine receptors (nAChR), which become up-regulated after chronic administration. Recent work has demonstrated that the recreational drug 3,4-methylenedioxymethamphetamine (MDMA) has affinity for nAChR and also induces up-regulation of nAChR in PC 12 cells. Tobacco and MDMA are often consumed together. In the present work we studied the in vivo effect of a classic chronic dosing schedule of MDMA in rats, alone or combined with a chronic schedule of NIC, on the density of nAChR and on serotonin reuptake transporters. MDMA induced significant decreases in [3H]paroxetine binding in the cortex and hippocampus measured 24 h after the last dose and these decreases were not modified by the association with NIC. In the prefrontal cortex, NIC and MDMA each induced significant increases in [3H]epibatidine binding (29.5 and 34.6%, respectively) with respect to saline-treated rats, and these increases were significantly potentiated (up to 72.1%) when the two drugs were associated. Also in this area, [3H]methyllycaconitine binding was increased a 42.1% with NIC + MDMA but not when they were given alone. In the hippocampus, MDMA potentiated the a7 regulatory effects of NIC (raising a 25.5% increase to 52.5%) but alone was devoid of effect. MDMA had no effect on heteromeric nAChR in striatum and a coronal section of the midbrain containing superior colliculi, geniculate nuclei, substantia nigra and ventral tegmental area. Specific immunoprecipitation of solubilised receptors suggests that the up-regulated heteromeric nAChRs contain a4 and b2 subunits. Western blots with specific a4 and a7 antibodies showed no significant differences between the groups, indicating that, as reported for nicotine, up-regulation caused by MDMA is due to post-translational events rather than increased receptor synthesis.
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1894/12/13 (A7,N323)-1894/12/19.
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1894/12/20 (A7,N324)-1894/12/27.
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1894/12/06 (A7,N322)-1894/12/12.
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1937 (A7,N3)- (A7,N4).
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1937 (A7,N1)- (A7,N2).
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1871/08/06 (A7).
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1908/04/04 (A7,N280).
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1908/01/18 (A7,N269).
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1908/08/22 (A7,N300).
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1908/10/31 (A7,N310).
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1908/05/23 (A7,N287).
