Current medicinal chemistry
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Ziconotide (PRIALT) is a neuroactive peptide in the final stages of clinical development as a novel non-opioid treatment for severe chronic pain. It is the synthetic equivalent of omega-MVIIA, a component of the venom of the marine snail, Conus magus. The mechanism of action underlying ziconotide's therapeutic profile derives from its potent and selective blockade of neuronal N-type voltage-sensitive calcium channels (N-VSCCs). ⋯ Contingent on regulatory approval, ziconotide will be the first in a new class of neurological drugs: the N-type calcium channel blockers, or NCCBs. Its novel mechanism of action as a non-opioid analgesic suggests ziconotide has the potential to play a valuable role in treatment regimens for severe chronic pain. If approved for clinical use, ziconotide will further validate the neuroactive venom peptides as a source of new and useful medicines.
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The well known calcium-sensitive phosphatase calcineurin is implicated in many eukaryotic activation and developmental programmes, including lymphocyte activation, heart-valve morphogenesis, angiogenesis, and neural and muscle development. The importance of this phosphatase is graphically illustrated by the observation that the immunosuppressive actions of the microbial drugs Cyclosporin A (CsA) and FK506 arise from their inhibition of calcineurin. As substrates of calcineurin, transcription factors of the NFAT family play an essential role in lymphocyte activation, and it follows that their function is also inhibited by CsA and FK506. ⋯ In a more recent development, specific amino acidic sequences implicated in the interaction between calcineurin and NFAT have been identified. It is of special interest that specific disruption of this pathway has been obtained through the expression of peptides based on some of these sequences. A more profound analysis of these issues could open up new perspectives in immunosuppressive therapy; promising compounds with features of endogenous calcineurin inhibitors (and thus likely to have fewer toxic effects than CsA and FK506), or selective blockers of calcineurin-NFAT interactions that would not alter the functioning of other calcineurin substrates.
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Review Comparative Study
New antipsychotics and schizophrenia: a review on efficacy and side effects.
The first compounds showing efficacy in the treatment of schizophrenia and other psychotic disorders was chlorpromazine, an anti-histaminic compound casually observed to possess antipsychotic effects. The discovery of the real mechanism of action of antipsychotic substances dates back to the 1960s, when researchers found that these compounds act as dopamine receptor antagonists. Unfortunately, this type of drugs cannot block the D2 receptors only in the mesolimbic dopaminergic pathway (which mediates their therapeutic effects), because of their non-selective D2 receptor blockage in both the mesolimbic and striatal regions, and the consequent appearance of side effects related to striatal interaction in the same dosage range as is needed for the therapeutical effects. ⋯ Later, other beneficial properties, such as improvement of negative symptoms and of cognitive dysfunction and efficacy in neuroleptic-resistant schizophrenia, were included in the definition of "atypical". In recent years, the appearance of new atypical antipsychotics (risperidone, olanzapine, quetiapine, ziprasidone) has opened new ways to therapy. The aim of this paper is to review literature about newer antipsychotics, focusing on their advantages in terms of efficacy and side effect profiles when compared to classical and older atypical antipsychotics, and to evaluate the efficacy of the different new antipsychotics when compared to one another.
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Review Comparative Study
Pharmacological approaches in the treatment of atrial fibrillation.
Atrial fibrillation (AF) is the most common sustained cardiac arrhythmia and is associated with substantial cardiovascular morbidity and mortality. The arrhythmia can be initiated and/or maintained by rapidly firing foci, single- and multiple-circuit reentry. Once initiated, AF alters atrial electrical and structural properties (atrial remodeling) in a way that promotes its own maintenance and recurrence and may alter the response to antiarrhythmic drugs. ⋯ The recent finding that angiotensin converting enzyme inhibitors and beta-blockers reduce the incidence of AF in patients post myocardial infarction with left ventricular dysfunction confirmed the importance of targeting the underlying arrhythmogenic substrate. This review focuses on the mechanisms underlying AF and the mechanism of action and the efficacy and safety profile of the ADs used in the treatment of atrial fibrillation. The advantages and disadvantages of rhythm and rate control, the role pill in a pocket concept and the role of the new ADs are dicussed.
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Although great progress has been made in our understanding of the molecular bases of mitochondrial disorders due to defects in the respiratory chain, little exists in the way of rational therapy. Possible therapeutic approaches include: palliative therapy; removal of noxious metabolites; administration of artificial electron acceptors, metabolites, and free radical scavengers; genetic counseling; and gene therapy. There has been progress with each of these approaches, although much work remains to be done. Finally, a novel approach to treating a specific mitochondrial disorder, MELAS, is presented.