صفحه محصول - پاورپوینت سایکوز یا روان پریشی

پاورپوینت سایکوز یا روان پریشی (pptx) 77 اسلاید

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نوع فایل : PowerPoint (.pptx) ( قابل ویرایش و آماده پرینت )

تعداد اسلاید: 77 اسلاید

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بنام خدا The Dopamine Hypothesis of Schizophrenia Several lines of evidence suggest that excessive limbic dopaminergic activity plays a role in psychosis: many antipsychotic drugs strongly block postsynaptic D2 receptors in the central nervous system, especially in the mesolimbic and striatal-frontal system; this includes partial dopamine agonists, such as aripiprazole Drugs that increase dopaminergic activity, such as levodopa, amphetamines, and bromocriptine and apomorphine, either aggravate schizophrenia psychosis or produce psychosis de novo in some patients. Dopamine-receptor density has been found postmortem to be increased in the brains of schizophrenics who have not been treated with antipsychotic drugs. The Dopamine Hypothesis of Schizophrenia However, the dopamine hypothesis is far from a complete explanation of all aspects of schizophrenia. The fact that several of the atypical antipsychotic drugs have much less effect on D2 receptors and yet are effective in schizophrenia has redirected attention to the role of other nondopamine receptors. The atypical antipsychotic drugs share the property of weak D2-receptor antagonism and more potent 5-HT2A-receptor blockade. The Serotonin Hypothesis of Schizophrenia indole hallucinogens such as LSD (lysergic acid diethylamide) and mescaline are serotonin (5-HT) agonists the identification of many 5-HT-receptor subtypes led to the pivotal discovery that 5-HT2A-receptor stimulation was the basis for the hallucinatory effects of these agents. 5-HT2A-receptor blockade is a key factor in the mechanism of action of the main class of atypical antipsychotic drugs such as clozapine These drugs are inverse agonists of the 5-HT2A receptor; that is, they block the constitutive activity of these receptors. These receptors modulate the release of dopamine in the cortex, limbic region, and striatum. 5-HT2C agonists are currently being studied as antipsychotic agents. Dopaminergic Systems Five important dopaminergic systems or pathways Mesolimbic-mesocortical pathway one most closely related to behavior and psychosis Nigrostriatal pathway it is involved in the coordination of voluntary movement. Blockade of the D2 receptors in the nigrostriatal pathway is responsible for EPS(extrapyramidal). Tuberoinfundibular system. Dopamine released by these neurons physiologically inhibits prolactin secretion from the anterior pituitary. Medullary-periventricular pathway This system may be involved in eating behavior. chemoreceptor trigger zone : inducesvomiting. The antipsychotic action is now thought to be produced (at least in part) by their ability to block dopamine in the mesolimbic and mesocortical systems.