Substance P primes the formation of hydrogen peroxide and nitric oxide in human neutrophils.
Substance P (SP), a neurotransmitter of the central and peripheral nervous system, has been implicated as a mediator of the pulmonary inflammatory response through its stimulatory effects on neutrophils. We investigated the role of SP in priming the production of reactive oxygen species by human neutrophils with the cytochrome c reduction assay and by flow cytometry using the intracellular oxidizable probe dichlorofluorescein. We also investigated SP-induced formation of nitrite and nitrate as an index of nitric oxide (NO) production. Our results indicate that SP primes two distinct pathways with respect to the induction of reactive oxygen species in the human neutrophil: the production of superoxide anion and hydrogen peroxide by the calmodulin-dependent NADPH oxidase, and the generation of NO by a constitutive NO synthase. Preincubation of neutrophils with inhibitors of calmodulin and NO synthase diminished the oxidative response in an additive fashion. These results give insight into distinct signal transduction pathways in the SP-primed neutrophil with respect to the formation of superoxide anion, hydrogen peroxide, and NO.
Sterner-Kock
A
A
Department of Anatomy, Physiology and Cell Biology, School of Veterinary Medicine, University of California, Davis 95616, USA.
Braun
R K
RK
van der Vliet
A
A
Schrenzel
M D
MD
McDonald
R J
RJ
Kabbur
M B
MB
Vulliet
P R
PR
Hyde
D M
DM
D000328:Adult; D005452:Fluoresceins / Q000378:metabolism; D006801:Humans; D006861:Hydrogen Peroxide / Q000378:metabolism*; D007249:Inflammation / Q000139:chemically induced; D018377:Neurotransmitter Agents / Q000494:pharmacology; D009504:Neutrophils / Q000378:metabolism* / Q000502:physiology; D009569:Nitric Oxide / Q000096:biosynthesis*; D016877:Oxidants / Q000378:metabolism; D010084:Oxidation-Reduction; D013373:Substance P / Q000494:pharmacology*; D013481:Superoxides / Q000097:blood
D005452:Fluoresceins; D018377:Neurotransmitter Agents; D016877:Oxidants; D013481:Superoxides; C029569:diacetyldichlorofluorescein; D009569:Nitric Oxide; D013373:Substance P; D006861:Hydrogen Peroxide