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Abstract: Several types of brain injuries have been associated with alterations in the striatal expression of neurotrophic factors, including glial cell line–derived neurotrophic factor (GDNF). However, contradictory results on the striatal expression of GDNF have been reported in different animal models of Parkinson''s disease. For this reason, we examined the effect of nigrostriatal damage on the mRNA and protein expression levels of GDNF in the striatum as a function of time following a striatal or medial forebrain bundle 6-hydroxydopamine lesion. At different time points after the administration of 6-hydroxydopamine, striatal expression levels of GDNF were analyzed with semi-quantitative Western blotting. No significant changes in GDNF expression levels were observed within the 35-day observation period, either between the denervated and the intact striatum of medial forebrain bundle and striatally lesioned rats or between the striata of lesioned animals and those of control animals. In order to reinforce these results, striata of lesioned rats, sacrificed 18 days after lesioning, were analyzed with enzyme-linked immunosorbent assay and real-time polymerase chain reaction. At this time point, both techniques confirmed the results of the Western blot analysis, detecting no changes in striatal expression of GDNF, either at the protein level, or at the mRNA level. These data show that nigrostriatal damage induced by 6-hydroxydopamine has no effect on the striatal expression of GDNF. [Copyright &y& Elsevier]

The purpose of the present study was to study the effect of an acute dose of the serotonin (5-HT) – noradrenaline (NA) reuptake inhibitor venlafaxine on extracellular concentrations of 5-HT, NA and dopamine (DA) in the hippocampus and on the peripheral hormone concentrations in freely moving rats. Blood obtained from a catheter placed in the vena femoralis was analyzed for adrenocorticotropin (ACTH), beta-endorphins, prolactin (PRL), growth hormone (GH) and cortisol. Collections are referred to pre and post injection of 20 mg/kg of venlafaxine. Extracellular hippocampal NA and 5-HT as determined with in vivo microdialysis increased significantly after drug injection. PRL and ACTH were significantly affected by the drug. At the selected dose venlafaxine is able to increase the release of 5-HT but also of NA in rat hippocampus. Due to the dual reuptake properties of the drug and the functional interconnection of the NA and the 5-HT systems, the observed effects on peripheral hormones are possibly mediated by a combined action of these 2 systems. [Copyright &y& Elsevier]