European Journal of Biomedical and Pharmaceutical Sciences

ROLE OF DOPAMINE D2 RECEPTOR IN CHOLINERGIC INTERNEURON IN RESPONSE TO COCAINE

Elmira Mofid MD*, Sukhrajwinder Sekhon MD, Casem Ballouk MD, Olha Huzo MD

ABSTRACT

Dopamine (DA) is the predominant catecholamine neurotransmitter in the human center nervous system, where it controls a variety of functions including cognition, emotion, locomotion activity, hunger and endocrine system regulation. The effects of the DA are brought about when DA interacts with the membrane bound dopamine receptors that belong to the G-protein coupled receptor family. There are five different types of DA receptors which are subdivided into two subfamilies; first, the D1-like that includes D1R, D5R and second, the D2-like that includes D2R, D3R and D4R. Dopamine is synthesized by the neurons of the substantial nigra and ventral tegmental area (VTA), and by hypothalamic neurons of the arcuate and periventricular nuclei (8). Projections originating from brain areas that synthesize this neurotransmitter give rise to four axonal pathways which are (i) nigro-striatal; (ii) mesolimbic; (iii) mesocortical; and (iv) tuberoinfundibular (7). The mesolimbic pathway originates from the midbrain VTA and innervates the ventral straitum, the olfactory tubercle (OT) and parts of the limbic system (7). This pathway has been implicated in the control of the reward mechanisms and in the psychomotor effects generated by drugs of abuse, including cocaine.

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