Amiloride (Am) dissociates human neutrophil (N) activation events
Human N can be stimulated to release granule contents and superoxide anion (O/sub 2/sup -//). These events are associated with an Am sensitive Na/sup +//H/sup +/ exchange and N alkalinization. Am has been reported to inhibit protein kinase C (PKC) in HL-60 cells. Due to the central role of PKC in N activation they assessed the effect of prolonged exposure of N to Am. When N were treated with 10/sup -6/ to 10/sup -3/M Am at 37/sup 0/C for 15 min a dose dependent inhibition of O/sub 2/sup -// release was seen upon N stimulation with FMLP (10/sup -6/M), A23187 (10/sup -5/M), or serum treated Zymosan (Z) (2.5 mg/ml). Maximal inhibition depended on the time of exposure of N to Am prior to stimulation and remained after removal of Am by washing. N treated with 10/sup -3/M Am had a decreased influx of /sup 45/Ca/sup + +/ upon stimulation with FMLP. Phorbol myristate acetate induced release of N O/sub 2/sup -// was unaffected by pretreatment with Am. Similarly, Am did not inhibit stimulated N lysozyme release or the incorporation of /sup 32/P into proteins. Monensin (a Na/sup +//H/sup +/ ionophore) did not correct the Am induced inhibition of O/sub 2/sup -// suggesting that cell acidification alone can not explain the Am effect. In conclusion: (1) Na/sup +//H/sup +/ exchange modulates N O/sub 2/sup -// release upon stimulation with FMLP, A23187, and Z. PMA induced N responses are not affected by cell acidification; (2) N granule release is under separate cellular control than O/sub 2/sup -//; (3) Am does not inhibit PKC or protein phosphorylation in N; and (4) decreased /sup 45/Ca/sup + +/ influx may partially explain the Am effect on FMLP induced O/sub 2/sup -// release.
- Research Organization:
- Univ. of Alabama, Birmingham
- OSTI ID:
- 7024860
- Report Number(s):
- CONF-8604222-
- Journal Information:
- Fed. Proc., Fed. Am. Soc. Exp. Biol.; (United States), Journal Name: Fed. Proc., Fed. Am. Soc. Exp. Biol.; (United States) Vol. 45:4; ISSN FEPRA
- Country of Publication:
- United States
- Language:
- English
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560300* -- Chemicals Metabolism & Toxicology
59 BASIC BIOLOGICAL SCIENCES
63 RADIATION, THERMAL, AND OTHER ENVIRON. POLLUTANT EFFECTS ON LIVING ORGS. AND BIOL. MAT.
ALKALINE EARTH ISOTOPES
ANIMALS
BETA DECAY RADIOISOTOPES
BETA-MINUS DECAY RADIOISOTOPES
BIOCHEMICAL REACTION KINETICS
BIOLOGICAL EFFECTS
BIOLOGICAL FUNCTIONS
BIOLOGICAL MATERIALS
BLOOD
BLOOD CELLS
BODY FLUIDS
CALCIUM 45
CALCIUM ISOTOPES
CARCINOGENS
DAYS LIVING RADIOISOTOPES
DIURETICS
DRUGS
ESTERS
EVEN-ODD NUCLEI
FUNCTIONS
INTERMEDIATE MASS NUCLEI
ISOTOPE APPLICATIONS
ISOTOPES
KINETICS
LEUKOCYTES
LIGHT NUCLEI
MAMMALS
MAN
MATERIALS
NEUTROPHILS
NUCLEI
ODD-ODD NUCLEI
ORGANIC COMPOUNDS
PHORBOL ESTERS
PHOSPHORUS 32
PHOSPHORUS ISOTOPES
PRIMATES
RADICALS
RADIOISOTOPES
REACTION KINETICS
SECRETION
SUPEROXIDE RADICALS
TRACER TECHNIQUES
VERTEBRATES