Dopamine modulation receptor subtype

Opioid binding at medullary sites is consistent with the respiratory depressant effects of the drugs. Binding in the nucleus accumbens and the resultant release of dopamine by the /x- and 8-opioids is linked to the development of physical dependence. However, the K-opioids, which also bind extensively in the nucleus accumbens, are linked to a decrease in dopamine release, possibly explaining their lower abuse liability. The localization of different receptor subtypes within different-size fiber pathways has been established. The x- and 8-receptors appear associated with the large-diameter fibers, while the K-receptors appear to be located in the small to medium-size fiber bundles of the dorsal root ganglia. Such differences may explain the modulation of specific types of nociceptive stimuli by the different opioid agonists and opioid peptides. 

The precise functions of the opioid receptor subtypes remain to be delineated. In many studies, it has been established that they modulate the functions of the dopaminergic system. For example, administration of morphine into the area 10 region results in a dopamine-dependent increase in locomotor activity. Electiophysiological studies of area 9 neurons suggest that p and k opioids have opposite effects on motor behaviors activation or sedation, respectively. The k and p agonists have also been found to exert opposite actions with respect to fluid regulation diuretic and... 

Zhang W, Yamada M, Gomeza J, Basile AS, Wess J (2002b) Multiple muscarinic acetylcholine receptor subtypes modulate striatal dopamine release, as studied with M1-M5 muscarinic receptor knock-out mice. J Neurosci 22 6347-52... 

O Kane EM, Stone TW (1998) Interaction between adenosine Ai and A2 receptor-mediated responses in the rat hippocampus in vitro. Eur J Pharmacol 362 17-25 Ohkubo S, Kimura J, Matsuoka I (2000) Ecto-alkaline phosphatase in NG108-15 cells a key enzyme mediating PI antagonist sensitive ATP response. Br J Pharmacol 131 1667-2 Okada M, Mizuno K, Kaneko S (1996) Adenosine Ai and A2 receptors modulate extracellular dopamine levels in rat striatum. Neurosci Lett 212 53-6 Okada M, Nutt DJ, Murakami T et al (2001) Adenosine receptor subtypes modulate two major functional pathways for hippocampal serotonin release. J Neurosci 21 628 40 Oliveira L, Correia-de-Sd P (2005) Protein kinase A and Cavl (L-Type) channels are common targets to facilitatory adenosine A2a and muscarinic Mj receptors on rat motoneurons. Neurosignals 14 262-72... 

Brunig I, Sommer M, Hatt H, Bormann J (1999) Dopamine receptor subtypes modulate olfactory bulb gamma-aminobutyric acid type A receptors. Proc Natl Acad Sci USA 96 2456-2460. 

In addition to immediate short-term effects on channel properties, dopamine also plays a key modulatory role in the regulation of neuronal responses mediated by activation of excitatory amino acid receptors. The nature of the modulatory effects of dopamine depend on the excitatory amino acid receptor subtype and the specific dopamine receptor subtype activated. The modulation of NMD A and AMPA receptors by dopamine Dl and D2 receptors has been reviewed recently by Cepeda et al. (1998) and Di Chiara et al. (1994). 

In various brain areas neuronal histamine release and synthesis is regulated presynaptically by histamine H3 receptors [1]. Recent studies revestl that H3 receptors not only act as autoreceptors to regulate the release euid synthesis of histamine [2, 3], but also modulate the release of other neurotransmitters, like acetylcholine [4], serotonin [5], dopamine [6] and noradrenaline [7]. In view of these widespread modulatory activities of the histamine H3 receptors, important roles for this receptor subtype in the various mammalian brain functions have been indicated [8, 9]. Consequently, selective ligands for the H3 receptor have been suggested to be benificial in the treatment of e.g. epilepsia, Alzheimer disease, sleeping and attention-deficit disorders [10, 11,12, 13, 14, 15,16],... 

Crawley JN Subtype-selective cholecystokinin receptor antagonists block cholecystokinin modulation of dopamine-mediated behaviors in the rat mesohmbic pathway. J Neurosci 12 3380-3391, 1992... 

Pettersson E, Herrera-Marschitz M, Rodriguez-Puerlas R, Xu ZQ, You ZB, Hughes J, Elde RP, Ungerstedt U, Hokfelt T (1996) Evidence for aspartate-immunoreactive neurons in the neostriatum of the rat modulation by the mesencephalic dopamine pathway via D1-subtype of receptor. Neuroscience 74 51-66. 

Amphetamines are potent agonists at trace amine-associated receptors (TAARs), and their effects may be mediated in part via TAARs and in part via dopamine transport [iR E] pijgj.g jg emerging evidence [3 ] that TAAR are activated by trace amines such as p-tyramine, P-phenylethylamine, tryptamine, and octopamine in mammalian brain and blood vessels [4 ] a subtype receptor, TAARi, is a modulator of the dopamine... 

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