Submitted to: Book Chapter
Publication Type: Book / Chapter
Publication Acceptance Date: May 27, 2004
Publication Date: N/A
Technical Abstract: In the central nerve system (CNS), dopamine (DA) is mainly in the three nerve systems: 1) the dopaminergic nigro-neostrial pathway, 2) the dopaminergic midbrain mesolimbic forebrain system, and 3) the dopaminergic tubero-infundibular system. Each dopaminergic system has distinctive functions in regulating physiological homeostasis. The dopaminergic nigro-neostrial pathway has functions in the integration of incoming sensory stimuli and the regulation of movement (controlling muscle tone and movement). The degeneration of dopaminergic neurons of the nigro-neostrial pathway is the hallmark of Parkinson's disease and several other neurological and psychiatric disorders. The dopaminergic midbrain mesolimbic forebrain system regulates cognitive, reward, mood, arousal, and sensomotor integration. Experimental studies showed that selective lesions of the dopaminergic neurons of the midbrain mesolimbic forebrain system cause cognitive deficits in rats or primates, especially when the mesocorticolimbic component of the DA is altered. The dopaminergic tubero-infundibular system is involved in neural regulation of the function of the hypothalamic-pituitary-adrenal (HPA) system in response to the internal and external stimulation. The endogenous DA secreted in the hypothalamus also exhibits a tonic inhibition of releasing Luteinizing hormone-releasing hormone (LHRH). Similarly, administration of exogenous DA causes a reduction of the LHRH level from the hypothalamus and less LH secretion from the pituitary. These effects of DA could either be verified by the administrating of DA receptor agonists, such as 2-Br-alpha-ergocryptine, or blocked by use of DA receptor blockers, such as haloperidol.