Ventral tegmental

In 1954, experiments by Olds and Milner revealed that the brain has specialized centers for reward functions. In these studies electrical stimulation of certain brain sites was found to be highly rewarding in the sense that rats operantly respond for electrical stimulation of these brain sites, often to the exclusion of any other activity. A neurotransmitter system that is particularly sensitive to electrical self-stimulation is the mesolimbic dopamine projection that originates in the ventral tegmental area and projects to structures closely... 

Rodd-Henricks ZA, McKinzie DL, Melendez Rl, et al Effects of serotonin-3 receptor antagonists on the intracranial self-administration of ethanol within the ventral tegmental area of Wistar rats. Psychopharmacology (Berl) 165 252—259, 2003... 

The rewarding effects of stimulants are mediated thtough the mesocotti-colimbic dopamine neutons of the ventral tegmental atea and theit tatget... 

Swartz CM, Breen K, Leone F Serum prolactin levels during extended cocaine abstinence. AmJ Psychiatry 147 777—779, 1990 Sziraki I, Sershen H, Hashim A, et al Receptors in the ventral tegmental area mediating nicotine-induced dopamine release in the nucleus accumbens. Neurochem Res 27 253-261, 2002... 

While the nigrostriatal pathways are ipsilateral some crossing occurs in fibres from the ventral tegmental AlO nucleus. These pathways are shown diagramatically in Fig. 7.1. Further details can be obtained from Moore and Bloom (1978) and Lindvall and Bjorkland (1978). The nuclei provide distinct loci for activating the dopamine systems for electrophysiological, release and behavioural studies and for their destruction by electrolytic lesion or injection of the toxin 6-hydroxydopamine (6-OHDA). 

Momiyama, T, Nao5uiki, T and Saso, M (1993) A mechanism underl5dng dopamine Di and D2 receptor-mediated inhibition of dopaminergic neurons in the ventral tegmental area in vitro. Br. J. Pharmacol. 109 933-940. 

The neuroehemical sites for psyehomotor stimulant reward are likely to be the presynaptic dopamine terminals located in the region of the nucleus aeeumbens, frontal cortex, and other forebrain structures that originate in the ventral tegmental area. Note, however, that intraeranial self-administration of eoeaine is elicited from the frontal cortex, but not from the nucleus aeeumbens (Goeders and Smith 1983). Thus, eoneomitant activation of structures other than the nucleus accumbens may be an important part of the circuitry involved in initiation of cocaine intravenous self-administration, as has been hypothesized for the opiates (Smith and Lane 1983 Smith et al. 1982). 

Roberts, D.C.S., and Koob, G.F. Disruption of eoeaine self-administration following 6-hydroxydopamine lesions of the ventral tegmental area in rats. Pharmacol Biochem Behav 17 901-904, 1982. 

QUESTION Is there a parallel to the reticulata component of the striatum, the dorsal striatum in the ventral tegmental area ... 

Olds, M.E. Amphetamine-induced increase in motor aetivity is correlated with higher firing rates of non-dopamine neurons in substantia nigra and ventral tegmental areas. Neurosci 24 477-490, 1988. 

Herve, D. Pickel, V.M. Joh, T.H. and Beaudet, A. Serotonin axon terminals in the ventral tegmental area of the rat Fine strueture and synaptie input to dopaminergic neurons. Brain Res 435 71-83, 1987. 

In this regard, considerable evidence shows that PCP increases dopaminergic transmission in the striatum (Johnson 1983) and, more recently, evidence indicates that DA function is increased in the mesolimbic and mesocortical pathways as well. For example, PCP administration has been shown to inhibit the firing of cells found in the ventral tegmental area (Freeman and Bunney 1984) similar to that observed in the substantia nigra (Raja and Guyenet 1980). 

O Virtually all abused substances appear to activate the same brain reward pathway. Key components of the reward pathway are the dopamine (DA) mesocorticolimbic system that projects from the ventral tegmental area (VTA) and the nucleus accumbens (NA) to the prefrontal cortex, the amygdala, and the olfactory tubercle (Figs. 33-3 and 33-4).5 Animal studies... 

French ED, Dillon K, Ali SF. Effects of Ibogaine, and cocaine and morphine after Ibo-gaine, on ventral tegmental dopamine neurons. Life Sci 1996 59 199-205. 

Lee, R. S., Steffensen, S. C. Henriksen, S. J. (2001). Discharge profiles of ventral tegmental area GABA neurons during movement, anesthesia, and the sleep-wake cycle. J. Neurosci. 21, 1757-66. 

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