PubMed · 12152121
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E Greco, P Polonio-Balbi, J C Speranza. 2002. Levosulpiride: a new solution for premature ejaculation?. https://doi.org/10.1038/sj.ijir.3900901
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Comparative molecular field analysis (CoMFA) has been widely used as a standard three dimensional quantitative structure-activity relationship (3D-QSAR) method. Although CoMFA is a useful technique, it does not always reflect real ligand-receptor interaction. Molecular interactions between the ligand and receptor are mainly occurred near the van der Waals surface of ligand. All grid points surrounding whole molecule in CoMFA are not important as molecular descriptors. If each molecule is represented by physico-chemical parameters on molecular surface, more precise and realistic 3D-QSAR is possible. We developed a new surface-based 3D-QSAR method using Kohonen neural network (KNN) and three-way partial least squares (3-way PLS). This method was applied to 25 dopamine 2 (D2) receptor antagonists for validation. First, the 3D coordinates of all sampling points on the van der Waals surface were projected into the 2D map by KNN. Each node in the map was coded by the associated molecular electrostatic potential (MEP) value of the original sampling point. Then, the correlation between the MEP values of all 2D maps and D2 receptor antagonist activities was analyzed by 3-way PLS. The statistics of the 3-way PLS model was excellent and the coefficients back-projected on the van der Waals surface had reasonable 3D distribution. Lastly, all data was divided into the calibration and validation sets by D-optimal designs and the activities of validation set were predicted. The external validation suggested that 3-way PLS is better than standard (2-way) PLS for prediction.
PURPOSE OF REVIEW: We aim to review recent neuroimaging contributions to our understanding of the cause and pathogenesis of Parkinson's disease, as well as treatment-related complications of disease, with a focus on functional anatomy and neurochemistry. RECENT FINDINGS: Recent reports describe altered dopaminergic activity in extrastriatal regions, as well as changes in other monoaminergic systems, such as serotonin. Attempts to correlate altered dopaminergic function with personality traits have also been described in the last year. The role of different markers of presynaptic dopaminergic integrity in the assessment of disease progression is discussed, as is the role of biomarkers in detection of preclinical disease. Cerebral activation studies not only confirm altered function of cortico-striatal-thalamo-cortical loops in Parkinson's, but also emphasize the importance of networks involving the cerebellum. The ability to detect changes in synaptic availability of dopamine using positron emission tomography with [(11)C]raclopride is reviewed, including the application to detect altered levels of dopamine in response to pharmacological, mechanical and behavioral stimuli. Such studies have been used to identify altered patterns associated with the development of motor fluctuations, as well as a biochemical substrate underlying the placebo effect in Parkinson's. SUMMARY: Functional imaging studies can provide novel insights into the etiopathogenesis of Parkinson's disease, as well as the mechanisms that contribute to complications of long-term therapy. They also shed light on the mechanisms that may underly behavioral changes and benefit derived from surgical interventions.