Ventral tegmental area, dopaminergic neurons

Fisher JL, Pidoplichko VI, Dani JA. (1998). Nicotine modifies the activity of ventral tegmental area dopaminergic neurons and hippocampal GABAergic neurons. J Physiol Paris. 92(3-4) 209-13. 

Mereu, G., Yoon, K., Gessa, G., Naes, L., and Westfall, T. (1987) Preferential stimulation of ventral tegmental area dopaminergic neurons by nicotine. Eur J Pharmacol 141 395-399. 

Matthews, Robert T., and Dwight C. German. 1984. "Electrophysiological Evidence for Excitation of Rat Ventral Tegmental Area Dopaminergic Neurons by Morphine." Neuroscience 11 617-26. 

Further examples for the simultaneous inhibitory effects of cannabinoids on antagonistic components of functional systems can be easily found. For example, cannabinoids inhibit the glutamatergic as well as the GABAergic input of ventral tegmental area dopaminergic neurons (Szabo et al. 2002 Melis et al. 2004) and the sympathetic as well as the parasympathetic input of the heart (Szabo et al. 2001). 

Korotkova T., Sergeeva O., Eriksson K., Haas H., Brown R. (2003). Excitation of ventral tegmental area dopaminergic and nondopaminergic neurons by orexins/hypocretins. J. Neurosci. 23, 7-11. 

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. 

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. 

Figure 7.4 Summary of some of the wide array of afferent and efferent connections of midbrain dopaminergic neurons (SN/A9, RRF/A8, and VTA/A10 in center of figure). This emphasizes their potential involvement in coordination of seemingly disparate behaviors inclusive of the sleep-wake state of the organism. Abbreviations BP, blood pressure BST, bed nucleus of the stria terminalis CEA, central nucleus of the amygdala MEA, midbrain extrapyramidal area NTS, nucleus of the solitary tract O2, oxygen tension PPN, pedunculopontine tegmental nucleus RRF, retrorubral field SN, substantia nigra VTA, ventral tegmental area.

Consistent with receptor binding studies, k receptor mRNA is expressed in the claustrum and interpeduncular nucleus as well as the ventral tegmental area. High levels of k receptor mRNA levels are expressed in the substantia nigra pars compacta, suggestive that k receptors may be expressed in dopaminergic neurons with a presynaptic location. 

Indirect mechanisms Nicotine has indirect effects on monoamine systems. A considerable amount of research has examined the relationships between nicotine and dopamine activity in the brain, in light of dopamine s role in reinforcement and nicotine s addictive properties. Nicotine increases dopamine turnover in the striatum and cerebral cortex (Clarke and Reuben 1996 Tani et al. 1997 Nanri et al. 1998). It also increases burst activity in dopamine neurons of the ventral tegmental area (VTA), a primary source of dopamine to the forebrain (Nisell et al. 1995 Fisher et al. 1998). Such a firing pattern in the VTA is associated with processes of reinforcement, learning, and cognitive activity. Nicotine actions on dopaminergic neurons occur at both somatodendritic sites and synaptic terminals. Further, both systemic nicotine and direct administration into the VTA increase dopamine release in the nucleus ac-... 

In contrast to acetylcholine, dopamine has both excitatory (Dl) and inhibitory (D2 and D3) receptors. Dopaminergic neurons occur in two closely connected groups AlO—ventral tegmental area (VTA), and A9—substantia nigra, pars compacta (Fig. 3). While substantia nigra neurons project to the striatum, VTA... 

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