Dopamine modulation physiology

Catecholamine A group of chemically similar compounds that are important in the modulation of cardiovascular activity and many other physiologic functions. Common catecholamines include epinephrine, norepinephrine, and dopamine. 

Like presynaptic dopamine autoreceptors, presynaptic histamine autoreceptors are activated by the released endogenous transmitter to inhibit further histamine release, as shown by the increase in histamine release caused by antagonists at H3 receptors a definite piece of physiology. Evidence has been presented recently that cardiac postganglionic sympathetic neurons of the guinea pig synthesize and release histamine as a co-transmitter (Li et al. 2003 2006). These noradrenaline-histamine neurons possess H3 autoreceptors which, when activated, depress the release of both noradrenaline and histamine - unlike the D2-like autoreceptors of dopamine-neurotensin neurons which modulate the release of the two cotransmitters in opposite direction (see Section 2.2). It would be of interest to see whether, conversely, activation of ot2-autoreceptors inhibits the release of histamine in the guinea pig heart. 

North RA (2002) Molecular Physiology of P2X Receptors. Physiol Rev 82 1013-67 Ohta K, Araki N, Shibata M, Komatsumoto S, Shimazu K, Fukuuchi Y (1994) Presynaptic ionotropic glutamate receptors modulate in vivo release and metabolism of striatal dopamine, noradrenaline, and 5-hydroxytryptamine involvement of both NMDA and AMPA/kainate sub-... 

Norepinephrine modulates many behavioral, cognitive, and physiological functions [72, 73], The catecholamine neurotransmitters dopamine and norepinephrine are stored in synaptic vesicles prior to release from the cell. It is within these vesicles that DpH is localized. Although most of the DpH is bound to the membrane of the vesicles, some DpH is free and is co-released with the catecholamines during synaptic transmission from neurons and into the blood from neurosecretory cells of the adrenal medulla [74], The levels found in serum are highly correlated between sibs, but varies between unrelated subjects [75], This variation has been found to be heritable in family and twin studies in both serum and CSF [76]. 

The naturally occurring catecholamines dopamine (1), norepinephrine (2), and epinephrine(3) (Figure 1) play key roles in neurotransmission, metabolism, and in the control of various physiological processes. For example, norepinephrine is the primary neurotransmitter in the sympathetic nervous system and also functions as a neurotransmitter in the central nervous system. Epinephrine, elaborated by the adrenal gland, has potent effects on the heart, vascular and other smooth muscles. Dopamine is an important neurotransmitter in the central nervous system, and has important peripheral effects in such organs as the kidney and heart. The importance of these effects has made the search for drugs that can mimic, inhibit, or otherwise modulate the effects of these catecholamines an important area of medicinal chemistry. 

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