Involvement of an NAD(P)H oxidase as a pO2 sensor protein in the rat carotid body.
The rat carotid body tissue reveals a photometrically measurable haem signal with absorbance maxima at 560 nm, 518 nm and 425 nm, suggesting the presence of a b-type cytochrome; this was confirmed by pyridine haemochrome and CO spectra. The quantity of cytochrome b was estimated to be 310 pmol.mg of protein-1. This haem is capable of H2O2 formation, which can be inhibited by 10 microM-diphenyliodonium (DPI). The hypoxia-induced increase in nervous chemoreceptor discharge and the reduction of FAD and NAD(P)+ were also inhibited by DPI (10 microM). These results suggest that an oxidase such as the NAD(P)H oxidase of neutrophils may act as a pO2 sensor protein in the rat carotid body, probably inducing the pO2 chemoreceptor process by H2O2 formation.
Cross
A R
AR
Department of Biochemistry, School of Medical Sciences, University of Bristol, U.K.
Henderson
L
L
Jones
O T
OT
Delpiano
M A
MA
Hentschel
J
J
Acker
H
H
D000818:Animals; D002344:Carotid Body / Q000166:cytology / Q000201:enzymology / Q000502:physiology*; D002628:Chemoreceptor Cells / Q000502:physiology*; D003573:Cytochrome b Group / Q000302:isolation & purification / Q000378:metabolism; D005182:Flavin-Adenine Dinucleotide / Q000032:analysis; D005456:Fluorescent Dyes; D009243:NAD / Q000032:analysis; D009247:NADH, NADPH Oxidoreductases / Q000378:metabolism*; D009249:NADP / Q000032:analysis; D019255:NADPH Oxidases; D010100:Oxygen / Q000032:analysis*; D051381:Rats; D020112:Rhodamine 123; D012235:Rhodamines; D013053:Spectrophotometry
D003573:Cytochrome b Group; D005456:Fluorescent Dyes; D012235:Rhodamines; D009243:NAD; D005182:Flavin-Adenine Dinucleotide; D020112:Rhodamine 123; D009249:NADP; D009247:NADH, NADPH Oxidoreductases; D019255:NADPH Oxidases; D010100:Oxygen