Classical antipsychotic drugs can mainly improvesymptoms, such as hallucination, delusion and thoughtdisorder but they almost have no effect on negativesymptoms, such as poverty of thinking process, apathy,will,abilityofloweredsocialde-creasedcommunication5-HT dysfunction could be involved in schizophrenia.Many effective antipsychotic drugs in addition toblocking dopamine receptors also act 5-HT, receptorantagonists. 5-HT has a modulatory effect on dopaminepathways, so the two theories are not incompatible
Classical antipsychotic drugs can mainly improve symptoms, such as hallucination, delusion and thought disorder but they almost have no effect on negative symptoms, such as poverty of thinking process, apathy, de-creased will, lowered ability of social communication. 5-HT dysfunction could be involved in schizophrenia. Many effective antipsychotic drugs in addition to blocking dopamine receptors also act 5-HT2 receptor antagonists. 5-HT has a modulatory effect on dopamine pathways, so the two theories are not incompatible
DopaminergicSystemsFive important dopaminergic system and pathways1.Mesolimbic-mesocortical pathwaywhich projects from cell bodies near nucleus substantianigra to the limbic system and neocortex.This system has connection with emotions2.Nigrostriatal pathwayIt consists of neurons that project from the substantia nigrato the caudate and putamenit is involved in the coordination of voluntary movement
Five important dopaminergic system and pathways. 1.Mesolimbic-mesocortical pathway which projects from cell bodies near nucleus substantia nigra to the limbic system and neocortex. This system has connection with emotions. 2.Nigrostriatal pathway It consists of neurons that project from the substantia nigra to the caudate and putamen. it is involved in the coordination of voluntary movement. Dopaminergic Systems
3. Tuberoinfundibular systemIt connects arcuate nuclei and periventricular neurons tothe hypothalamus and posterior pituitaryDopamine released by these neurons physiologicallyinhibits prolactin secretion4. Medullary-periventricular pathwayIt consists of neurons in the motor nucleus of the vagusThis system may be involved in eating behavior5.Incertohypothalamic pathwayIt forms connections with the hypothalamus and to thelateral septal nucleiIts functions are not yet defined
3. Tuberoinfundibular system It connects arcuate nuclei and periventricular neurons to the hypothalamus and posterior pituitary. Dopamine released by these neurons physiologically inhibits prolactin secretion. 4. Medullary-periventricular pathway It consists of neurons in the motor nucleus of the vagus. This system may be involved in eating behavior. 5.Incertohypothalamic pathway It forms connections with the hypothalamus and to the lateral septal nuclei. Its functions are not yet defined
BRAIN:SAGGITALVIEWDOPAMTNERGICPATHWAYSCINGULATEYRUSMEUIALFOREBRAINCORPUSBUNDLECALLOSUMBASALFORNIXGANGLTASUBSTANTIANPRAHVPOPHYSISVENTRALHIPPOCAMPUSTEGMENTUMPONSMEDULLAThe extensive connections of dopaminergic pathways are shown in red
The extensive connections of dopaminergic pathways are shown in red
Dopamine ReceptorsFive types of dopamine receptors1.D, receptor:It coupling with adenylate cyclase, increases cAMP, isdistributed postsynapticallyIt is found mainly in putamen, nucleus accumbens andolfactory tubercle.Peripherally vascular D, receptor is located in renal.mesenteric and coronary beds. The activation of Dreceptor induces vasodilatation and the increase ofmyocardial contractility
Five types of dopamine receptors 1.D1 receptor: It coupling with adenylate cyclase, increases cAMP, is distributed postsynaptically. It is found mainly in putamen, nucleus accumbens and olfactory tubercle. Peripherally vascular D1 receptor is located in renal, mesenteric and coronary beds. The activation of D1 receptor induces vasodilatation and the increase of myocardial contractility. Dopamine Receptors