Author
David S. Bredt
Other affiliations: Johns Hopkins University, Georgetown University Medical Center, Eli Lilly and Company ...read more
Bio: David S. Bredt is an academic researcher from Johnson & Johnson. The author has contributed to research in topics: Nitric oxide synthase & Nitric oxide. The author has an hindex of 107, co-authored 223 publications receiving 62332 citations. Previous affiliations of David S. Bredt include Johns Hopkins University & Georgetown University Medical Center.
Papers published on a yearly basis
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TL;DR: It is shown that nitric oxide synthetase activity requires calmodulin, and the native enzyme appears to be a monomer.
Abstract: Nitric oxide mediates vascular relaxing effects of endothelial cells, cytotoxic actions of macrophages and neutrophils, and influences of excitatory amino acids on cerebellar cyclic GMP. Its enzymatic formation from arginine by a soluble enzyme associated with stoichiometric production of citrulline requires NADPH and Ca2+. We show that nitric oxide synthetase activity requires calmodulin. Utilizing a 2',5'-ADP affinity column eluted with NADPH, we have purified nitric oxide synthetase 6000-fold to homogeneity from rat cerebellum. The purified enzyme migrates as a single 150-kDa band on SDS/PAGE, and the native enzyme appears to be a monomer.
3,206 citations
01 Jan 2016
TL;DR: In this paper, it was shown that NO synthetase is a calmodulin-requiring enzyme, and showed that NO formation is accompanied by the stoichiometric conversion of arginine to citrulline.
Abstract: Nitric oxide mediates vascular relaxing effects of endothelial cells, cytotoxic actions of macrophages and neu- trophils, and influences of excitatory amino acids on cerebellar cyclic GMP. Its enzymatic formation from arginine by a soluble enzyme associated with stoichiometric production of citruline requires NADPH and Ca2 . We show that nitric oxide synthetase activity requires calmodulin. Utilizing a 2',5'-ADP affmity col- umn eluted with NADPH, we have purified nitric oxide synthetase 6000-fold to homogeneity from rat cerebellum. The purified enzyme migrates as a single 150-kDa band on SDS/PAGE, and the native enzyme appears to be a monomer. Endothelium-derived relaxing factor, a labile substance formed by endothelial cells, which mediates vasodilation, has been shown to be identical to nitric oxide (NO) (1-3). In addition to relaxing blood vessels, NO has multiple messen- ger functions as it has been demonstrated in macrophages (4) and in brain tissue (5-7). NO appears responsible for the cytotoxic effects of macrophages and neutrophils (8). We have obtained direct evidence for NO as a messenger for the influences of the excitatory amino acid glutamate on cGMP in the cerebellum (7). We showed a striking enhancement by glutamate and other excitatory amino acids of the conversion of arginine to NO and the associated formation of citrulline. Moreover we observed that Nw-monomethyl-L-arginine (MeArg), an inhibitor of the enzymatic conversion of arginine to NO, inhibits glutamate-elicited cGMP formation, an influ- ence selectively reversed by excess arginine. Evidence that NO mediates functions of tissues as diverse as the brain, endothelium, and blood cells suggests a wide- spread role for NO as a messenger molecule. Localizing NO formation at a cellular level throughout the body would be greatly facilitated by immunohistochemical identification of NO synthetase, the NO-forming enzyme. The mechanism of conversion of arginine to NO, presently unclear (9), would be greatly clarified by purification of NO synthetase. Charac- terization of this enzyme has been hampered by the complex assays required to assay the enzyme by monitoring NO formation directly. We have shown that NO formation is accompanied by the stoichiometric conversion of arginine to citrulline, permitting a simple, sensitive, and specific enzyme assay measuring the transformation of (3H)arginine to (3H)citrulline (7). Utilizing this assay in the present study, we have purified NO synthetase to homogeneity. We demon- strate that NO synthetase is a calmodulin-requiring enzyme, explaining numerous reports of a crucial role for calcium in endothelium-dependent smooth muscle relaxation.
3,082 citations
TL;DR: It is demonstrated that NO synthase in the brain to be exclusively associated with discrete neuronal populations, and prominent neural localizations provided the first conclusive evidence for a strong association of NO with neurons.
Abstract: Nitric oxide (NO), apparently identical to endothelium-derived relaxing factor in blood vessels, is also formed by cytotoxic macrophages, in adrenal gland and in brain tissue, where it mediates the stimulation by glutamate of cyclic GMP formation in the cerebellum Stimulation of intestinal or anococcygeal nerves liberates NO, and the resultant muscle relaxation is blocked by arginine derivatives that inhibit NO synthesis It is, however, unclear whether in brain or intestine, NO released following nerve stimulation is formed in neurons, glia, fibroblasts, muscle or blood cells, all of which occur in proximity to neurons and so could account for effects of nerve stimulation on cGMP and muscle tone We have now localized NO synthase protein immunohistochemically in the rat using antisera to the purified enzyme We demonstrate NO synthase in the brain to be exclusively associated with discrete neuronal populations NO synthase is also concentrated in the neural innervation of the posterior pituitary, in autonomic nerve fibres in the retina, in cell bodies and nerve fibres in the myenteric plexus of the intestine, in adrenal medulla, and in vascular endothelial cells These prominent neural localizations provide the first conclusive evidence for a strong association of NO with neurons
2,979 citations
2,344 citations
TL;DR: Cloning of a complementary DNA for brain nitric oxide synthase reveals recognition sites for NADPH, FAD, flavin mononucleotide and calmodulin as well as phosphorylation sites, indicating that the synthase is regulated by many different factors.
Abstract: Nitric oxide is a messenger molecule, mediating the effect of endothelium-derived relaxing factor in blood vessels and the cytotoxic actions of macrophages, and playing a part in neuronal communication in the brain. Cloning of a complementary DNA for brain nitric oxide synthase reveals recognition sites for NADPH, FAD, flavin mononucleotide and calmodulin as well as phosphorylation sites, indicating that the synthase is regulated by many different factors. The only known mammalian enzyme with close homology is cytochrome P-450 reductase.
2,302 citations
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TL;DR: Attention is focussed on the ROS/RNS-linked pathogenesis of cancer, cardiovascular disease, atherosclerosis, hypertension, ischemia/reperfusion injury, diabetes mellitus, neurodegenerative diseases, rheumatoid arthritis, and ageing.
12,240 citations
TL;DR: The best understood form of long-term potentiation is induced by the activation of the N-methyl-d-aspartate receptor complex, which allows electrical events at the postsynaptic membrane to be transduced into chemical signals which, in turn, are thought to activate both pre- and post Synaptic mechanisms to generate a persistent increase in synaptic strength.
Abstract: Long-term potentiation of synaptic transmission in the hippocampus is the primary experimental model for investigating the synaptic basis of learning and memory in vertebrates. The best understood form of long-term potentiation is induced by the activation of the N-methyl-D-aspartate receptor complex. This subtype of glutamate receptor endows long-term potentiation with Hebbian characteristics, and allows electrical events at the postsynaptic membrane to be transduced into chemical signals which, in turn, are thought to activate both pre- and postsynaptic mechanisms to generate a persistent increase in synaptic strength.
11,123 citations
TL;DR: There is growing evidence that aging involves, in addition, progressive changes in free radical-mediated regulatory processes that result in altered gene expression.
Abstract: At high concentrations, free radicals and radical-derived, nonradical reactive species are hazardous for living organisms and damage all major cellular constituents. At moderate concentrations, how...
9,131 citations
TL;DR: The discovery that mammalian cells generate nitric oxide, a gas previously considered to be merely an atmospheric pollutant, is providing important information about many biologic processes.
Abstract: The discovery that mammalian cells generate nitric oxide, a gas previously considered to be merely an atmospheric pollutant, is providing important information about many biologic processes. Nitric oxide is synthesized from the amino acid L-arginine by a family of enzymes, the nitric oxide synthases, through a hitherto unrecognized metabolic route -- namely, the L-arginine-nitric oxide pathway1–8. The synthesis of nitric oxide by vascular endothelium is responsible for the vasodilator tone that is essential for the regulation of blood pressure. In the central nervous system nitric oxide is a neurotransmitter that underpins several functions, including the formation of memory. . . .
6,464 citations
TL;DR: Inositol trisphosphate is a second messenger that controls many cellular processes by generating internal calcium signals through receptors whose molecular and physiological properties closely resemble the calcium-mobilizing ryanodine receptors of muscle.
Abstract: Inositol trisphosphate is a second messenger that controls many cellular processes by generating internal calcium signals. It operates through receptors whose molecular and physiological properties closely resemble the calcium-mobilizing ryanodine receptors of muscle. This family of intracellular calcium channels displays the regenerative process of calcium-induced calcium release responsible for the complex spatiotemporal patterns of calcium waves and oscillations. Such a dynamic signalling pathway controls many cellular processes, including fertilization, cell growth, transformation, secretion, smooth muscle contraction, sensory perception and neuronal signalling.
6,389 citations