Dopamine receptor agonists nervous system

Nervous system Somnolence is a common adverse reaction to dopamine receptor agonists. The spouse of a man taking rotigotine became excessively somnolent, and the effect disappeared when he started to use... 

Nervous system Sleep attacks Sleep attacks attributable to dopamine receptor agonists continue to be reported. 

Nicotine is an agonist at the nicotinic acetylcholine receptor (nAChR). Activation of this receptor depolarizes target cells (see Ch. 11). nAChRs are composed of five subunits surrounding a central ion-channel pore. Twelve different nicotinic receptor subunits are expressed in the nervous system (a2-oclO and (32—134). Of these, a subset is expressed in the VTA (a3-a7 and P2—134). It is thought that a7 receptors form homomeric receptors a3, a4 and a6 form heteromeric channels with 02 or 04 and a5 and 03 can associate with other a/0 pairs. Studies in knockout mice implicate several subunits in the ability of nicotine to modulate dopamine neurons (a4, a6, a7, 02, 03) but... 

Catecholamines, 6 (1969) 200 Cell membrane transfer, 14(1977) 1 Central nervous system, drugs, transmitters and peptides, 23 (1986) 91 Centrally acting dopamine D2 receptor agonists, 29 (1992) 185 Chartreusin, 19 (1982) 249 Chelating agents, 20 (1983) 225... 

Both drugs are partial agonists at a-adrenergic receptors and at some serotonin and dopamine receptors they also can inhibit the release of endotheUal-derived relaxation factor. They may induce arterial vasoconstriction and have minor actions on the central nervous system. Their a-adrenergic blocking activity is relatively weak compared with those of other ergot alkaloids. 

Dopamine agonists decrease pituitary prolactin secretion through a dopamine-mimetic action on the pituitary at two central nervous system loci (1) they decrease dopamine turnover in the tuberoinfundibular neurons of the arcuate nucleus, generating increased hypothalamic dopamine and (2) they act directly on pituitary dopamine receptors to inhibit prolactin release. 

The recognition that dopamine (DA) Is an important neurotransmitter with receptors in both the central nervous system and in the periphery has resulted in a widespread search for substances that either mimic or block the action of this natural neurotransmitter on Its receptors. This has resulted in the discovery of an enormous number of compounds of diverse structure that have DA receptor agonist and antagonist properties. 

LSD acts on several sites in the central nervous system. It is a nonselective serotonin, or 5-hydroxy-tryptamine (5-HT) agonist on both presynaptic and postsynaptic receptor sites. The 5-HT2a receptor agonism is implicated in the modulation of hallucinations. In addition to the role of serotonin in causing hallucinations, other neurotransmitters, including glutamate and Di and D2 dopamine receptors, are implicated yet, their role remains elusive. 

Morphine is the prototype for the class of natural and synthetic opioid analgesics and its toxicity stems mainly from its extensive effect on the central nervous system (CNS), principally that of a descending depression. Opioids interact with stereospecific and saturable binding sites mostly located in the CNS. Interaction with the opioid receptors mimics the actions of endogenous enkephalins and endorphins. Morphine is a pure opiate agonist and exerts its activity primarily on the mu receptor. Activity also appears to involve an alteration in the release of neurotransmitters, such as the inhibition of acetylcholine, norepinepherine, and dopamine. These actions result in the therapeutic effects of analgesia, sedation, euphoria, and decreased gastrointestinal motility however, in toxic amounts they can lead to... 

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