Nitric Oxide Synthase in Bovine Superior Cervical Ganglion |
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| Authors: | Hong Sheng Gerard D Gagne† Takahiro Matsumoto‡ Mahlon F Miller† Ulrich Förstermann‡ Ferid Murad‡ |
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| Institution: | Department of Vascular Biology, Abbott Laboratories, Abbott Park, U.S.A.;Department of Cellular and Microscopic Research, Abbott Laboratories, Abbott Park, U.S.A.;Department of Pharmacology, Northwestern University Medical School, Chicago, Illinois, U.S.A. |
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| Abstract: | Abstract: We investigated the mechanism of increases in cyclic GMP levels in bovine superior cervical ganglion (SCG) in response to muscarinic receptor stimulation. Acetylcholine increased cyclic GMP levels in SCG. This increase was inhibited by N G-methyl-L-arginine (NMA), and the inhibition was reversed by L-arginine. Soluble nitric oxide (NO) synthase was partially purified from bovine SCG using 2',5'-ADP Sepharose affinity chromatography. The resulting enzyme activity was Ca2+/calmodulin dependent and required NADPH and tetrahydrobiopterin as co-factors. Superoxide dismutase protected and oxyhemo-globin blocked the effect of NO formed by the enzyme. NMA inhibited the activity of the NO synthase. In western blots, an antibody generated against rat brain NO synthase specifically recognized the NO synthase from SCG as a 155-kDa protein band. Immunohisto chemistry using the same antibody demonstrated that NO synthase was localized in postganglionic neuronal cell bodies of the SCG. Immunofluorescent labeling showed that some of the cells staining positive for dopamine-β-hydroxylase also contained NO synthase. Thus, NO is synthesized in specific cells within bovine SCG, including sympathetic neurons, and mediates the acetylcholine-induced stimulation of soluble guanylyl cyclase. |
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| Keywords: | Acetylcholine L-Arginine N G-Methyl-L-arginine Calcium Calmodulin Cyclic GMP Dopamine-β-hydroxylase Immunohistochemistry Sympathetic neuron |
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