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Abstract: Dopamine may alter the phosphorylation state of DARPP-32 that plays a central role in the dopaminergic neurons biology. Studies have shown that DARPP-32/protein phosphatase 1 cascade is a major target for psychostimulants drugs. Methylphenidate is a psychostimulant that acts blocking the dopamine transporter has been used as an effective treatment for Attention Deficit Hyperactivity Disorder. We investigated if methylphenidate could alter DARPP-32 expression in five brain regions (striatum, hippocampus, prefrontal cortex, cortex and cerebellum) in young and adult rats. Our results showed that methylphenidate treatment is able to alter DARPP-32 expression in rat brain. Acute methylphenidate treatment has reduced hippocampal DARPP-32 protein levels in old rats, while chronic methylphenidate treatment has decreased them in old rat hippocampus and young rat cerebellum. It was found an increased cortical expression after chronic methylphenidate administration in old rats. Our results provide the first experimental demonstration that methylphenidate induces changes in total DARPP-32 expression that are posology- and age-related in some rat brain areas, although further studies are needed to shed more light on the mechanisms behind these findings. [Copyright &y& Elsevier]

Background and Objectives: The neuraxial techniques currently represent the most effective methods for pain control during labor and the epidural block using ultradiluted anesthetic solutions is considered the gold standard promoting adequate pain relief with minimum side effects. In some situations however the use of these techniques is limited by the existence of maternal contraindications, or structural or material obstacles. In these cases, the alternatives are still precarious and scarce offering little optimistic results and of dubious effectiveness., Content: This article presents through a literature review the available information on the use of remifentanil as an alternative technique for analgesia during labor discussing aspects of pharmacokinetics, analgesia efficacy, maternal satisfaction and maternal/fetal side effects., Conclusions: The initial data show that remifentanil is a promising option to be employed in situations where the parturient cannot or does not want to receive the neuraxial analgesia., (Copyright 2010 Elsevier Editora Ltda. All rights reserved.)