Brain nucleus accumbens

Hi-receptors in the adrenal medulla stimulates the release of the two catecholamines noradrenaline and adrenaline as well as enkephalins. In the heart, histamine produces negative inotropic effects via Hr receptor stimulation, but these are normally masked by the positive effects of H2-receptor stimulation on heart rate and force of contraction. Histamine Hi-receptors are widely distributed in human brain and highest densities are found in neocortex, hippocampus, nucleus accumbens, thalamus and posterior hypothalamus where they predominantly excite neuronal activity. Histamine Hrreceptor stimulation can also activate peripheral sensory nerve endings leading to itching and a surrounding vasodilatation ( flare ) due to an axonal reflex and the consequent release of peptide neurotransmitters from collateral nerve endings. 

Yan QS Activation of 5-HT2a/2C receptors within the nucleus accumbens increases local dopaminergic transmission. Brain Res Bull 31 75-81, 2000... 

In other brain areas which receive a DA input, such as the nucleus accumbens and prefrontal cortex, it appears to be inhibitory and predominently D2-mediated. This is clear from Fig. 7.5 which shows inhibition by apomorphine (mixed D2, Di agonists) of the firing of neurons in the medial prefrontal cortex of the anaesthetised rat and its antagonism by the D2 antagonist haloperidol. 

Kelly, P.H. Seviour, P. and Iversen, S.D. Amphetamine and apomorphine response in the rat following 6-OHDA lesions of the nucleus accumbens septi and corpus striatum. Brain Res 94 507-522, 1975. 

Hernandez, L. Lee, F. and Hoebel, B.G. Simultaneous microdialysis and amphetamine infusions in the nucleus accumbens and striatum of freely moving rats Increase in extracellular dopamine and serotonin. Brain Res Bull 19 623-628, 1987. 

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... 

Cory-Slechta DA, Pazmino R, Bare C. 1997a. The critical role of nucleus accumbens dopamine systems in the mediation of fixed interval schedule-controlled operant behavior. Brain Res 764 248-256. 

Nation JR, Burkey RT. 1994. Attenuation of cocaine-induced elevation of nucleus accumbens dopamine in lead-exposed rats. Brain Res Bull 35 101-105. 

Van Bockstaele, E. J., Biswas, A. Pickel, V. M. (1993). Topography of serotonin neurons in the dorsal raphe nucleus that send axon collaterals to the rat prefrontal cortex and nucleus accumbens. Brain Res. 624, 188-98. 

Hurd, Y.L., Weiss, F., Koob, G., and Ungerstedt, U., Cocaine reinforcement and extracellular dopamine overflow in the rat nucleus accumbens an in vivo microdialysis study, Brain Res., 498, 199, 1989. 

Izenwasser, S. and Cox, B.M., Daily cocaine treatment produces a persistent reduction of [3H]dopam-ine uptake in vitro in the rat nucleus accumbens but not the striatum, Brain Res., 531, 338, 1990. 

Steinpreis, R.E. and Salamone, J.D., The role of nucleus accumbens dopamine in the neurochemical and behavioral effects of phencyclidine a microdialysis and behavioral study, Brain Res., 612, 263,1993. 

Chen, J., Paredes, W., Li, J., Smith, D., Lowinson, J., and Gardner, E.L., In vivo brain microdialysis studies of A9-tetrahydrocannabinol on presynaptic dopamine efflux in nucleus accumbens of the Lewis rat, Psychopharmacology, 102, 156, 1990. 

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