Blood vessels nitric oxide affecting

The role of CuZnSOD on oxygen radical production in cerebral vessels has been studied. Didion et al. [28] demonstrated that endogenous CuZnSOD diminished superoxide levels in rabbit cerebral blood vessels and affected nitric oxide- and cyclooxygenase-mediated responses in cerebral microcirculation. A subsequent study by the same group [29] showed increased superoxide production and vascular dysfunction in CuZnSOD-deficient mice. Chang et al. [30] suggested that superoxide induced cytokines, which activated microglial... 

The latest entrant in the neurotransmitter lineup is NO, nitric oxide, the first neurotransmitter discovered in the gas phase. For decades physicians and pharmacologists have been aware of the ability of nitrates to dilate blood vessels. Compounds like nitroglycerin are key tools in the control of angina pectoris, constriction of the coronary arteries. Yet no one knew exactly how the nitrates performed their feat until recently. The notariety of Viagra attests to the interest in products which affect NO systems. More about the synthesis and actions of NO will be described shortly. 

The same cardiovascular control system regulates blood distribution and blood pressure by affecting the small arterioles of the peripheral blood vasculature. The entrance to each of these vessels is surrounded by a sphincter muscle (a ring of involuntary muscle that surrounds the arteriolar aperture) with sympathetic, and in some cases, parasympathetic, nerve fibers. The sphincter is usually contracted. When the signal comes for the muscle to relax, the neuron produces nitric oxide at the neuromuscular junction, and this gas relaxes the sphincter. When the sphincter muscle expands, it increases the area through which blood flows and decreases its resistance. With decreased resistance, blood pressure falls. 

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