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Biomedical subjects

Xin Min Li

Publications and source records attributed to Xin Min Li.

4 recordsLinked to original sources

Differential regulation of hippocampal BDNF mRNA by typical and atypical antipsychotic administration.

Apart from their differential propensities to block dopamine D2 and serotonin 5-HT2 receptors, the molecular mechanisms underlying the clinical efficacy of typical and atypical antipsychotics in schizophrenia are largely unknown. Given recent interest in the effects of antipsychotics on neurotrophic and other growth related factors, the effects of antipsychotics on brain-derived neurotrophic factor (BDNF), a neurotrophin crucial to the structural integrity of adult neurons, were investigated in male Wistar rats. Chronic (19 day) but not acute (45 min) antipsychotic administration significantly altered levels of hippocampal BDNF mRNA. In addition, whereas chronic treatment with the strong D2 receptor-blocker haloperidol significantly downregulated hippocampal BDNF mRNA, the selective 5-HT2 receptor-blocker ritanserin significantly upregulated CA1 hippocampal BDNF mRNA in comparison to controls. Since high doses of risperidone and clozapine produce potent inhibition of both 5-HT2 and D2 receptors, while lower doses produce significantly greater 5-HT2 vs. D2 receptor blockade, a dose-response study was employed to determine whether low doses of these atypical antipsychotics would also upregulate hippocampal BDNF mRNA in the absence of significant D2 receptor blockade. Whereas chronic haloperidol and high-dose risperidone significantly downregulated hippocampal BDNF mRNA, intermediate and lower doses of risperidone and clozapine were, unlike ritanserin, without effect when compared to controls. Thus, although the long-term downregulation of hippocampal BDNF mRNA may underlie the different clinical profiles of certain antipsychotics, this effect seems to be associated with antipsychotic doses that not only cause significant D2 receptor inhibition, but are usually associated with side effects rather than therapeutic efficacies.

Animals↗

Quetiapine attenuates the immobilization stress-induced decrease of brain-derived neurotrophic factor expression in rat hippocampus.

Quetiapine is a new atypical antipsychotic drug widely used in the treatment of schizophrenia and other psychotic disorders. This study examined the influence of quetiapine on the decrease of brain-derived neurotrophic factor (BDNF) expression, induced by chronic immobilization stress, in the hippocampus of the rat. Pretreatment with 10 mg/kg of quetiapine markedly attenuated the stress-induced decrease in levels of BDNF protein, as determined by Western blot analyses, and the reduction of BDNF immunoreactivity, in hippocampal pyramidal and dentate granular neurons. These results suggest that the chronic administration of quetiapine could be neuroprotective to hippocampal neurons in schizophrenia and this effect may be related to its antipsychotic effect in patients with schizophrenia.

Animals↗

Total cavopulmonary connection with extraatrial tunnel.

Between April 1997 and February 2000, total cavopulmonary connection with an extraatrial tunnel was used to treat 9 cases of complicated congenital heart disease: single ventricle (4), double-outlet right ventricle (3), mitral atresia (1), and tricuspid atresia (1). There was no mortality. One patient developed bacterial endocarditis and required reoperation after 52 days to replace the tunnel. At follow-up ranging from 11 months to 3 years, 3 patients were in New York Heart Association functional class I, and 6 were in class II. One patient with single ventricle had refractory supraventricular tachycardia after a modified Fontan operation 4 years earlier, which was cured by the total cavopulmonary connection procedure. The essential factors for a good outcome include appropriate surgical indication, avoidance of aortic crossclamping and cardiac arrest, and unobstructed anastomosis between the superior and inferior venae cavae and the pulmonary artery.

Adolescent↗