Dopamine and Its Modulation of Drug-Induced Neuronal Damage

Abstract

Dopamine (DA), or 3-hydroxytyramine, is a chemical species that has immense importance for the proper functioning of a number of the body’s organ systems. Perhaps DA exerts its most profound influence in its role as a neurotransmitter. DA is distributed in a rather discrete manner throughout the central nervous system (CNS), with its cell bodies originating in the mesencephalon. Its axonal processes ramify from here to many distant sites where DA participates in the process of neuronal communication. As a neurotransmitter, DA is known to mediate a wide-variety of physiological processes and behaviors including locomotor activity, modulation of the cardiovascular system, food-intake, regulation of body temperature, and neuroendocrine function, to mention but a few. DA also mediates the reinforcing effects of a number of psychostimulant drugs of abuse such as cocaine and the amphetamines. In a broader sense, DA is actually considered the neurotransmitter in the brain’s pleasure center (i.e., the nucleus accumbens) where it decodes the reinforcing effects of diverse stimuli. When the DA neuronal system does not function properly, it is possible that the ensuing disruption in higher-cognitive processes can lead to psychiatric illness. Furthermore, if the nigrostriatal DA system damaged or destroyed, the effects can manifest themselves as a neurological disorder, and Parkinson’s disease (PD) is the best known example of this. Therefore, the DA neuronal system is extremely important to brain function and it maintains a delicate balance between normal function and dysfunction.