Sialic acid residues play a pivotal role in α1-acid glycoprotein (AGP)-induced generation of reactive oxygen species in chemotactic peptide pre-activated neutrophil granulocytes

The response to D-glucose (0–21 mM) was studied in neutrophil granulocytes from obese, hyperglycemic and hyperinsulinemic Umeå ob/ob mice and their lean, littermate controls in order to further elucidate the effects of in vivo and in vitro hyperglycemia on neutrophil function. Neutrophil random locomotion on glass and neutrophil resting luminol-enhanced chemiluminescence in cell suspension were studied. Random locomotion was stimulated by D-glucose in neutrophils from both Umeå ob/ob and control mice but the locomotive activity in Umeå ob/ob mouse neutrophils was significantly higher than that found in the controls at 4–21 mM glucose. In both types of mice, the stimulatory effect of D-glucose on random locomotion was diminished at 21 mM glucose (not significantly different from that at 0 mM glucose). Resting chemiluminescence from mouse neutrophils was also stimulated by glucose but here the magnitude of response was similar in neutrophils from both types of mice. These results indicate that chronic hyperglycemia and hyperinsulinemia in the Umeå ob/ob mouse may be associated with an increased neutrophil random locomotive activity but a similar resting production of reactive oxygen species, as compared with neutrophils from control mice at physiological and hyperglycemic glucose concentrations in vitro.

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Mechanisms of pulmonary vasoconstriction induced by chemotactic peptide FMLP in isolated rabbit lungs

Journal of Applied Physiology ◽

10.1152/jappl.1992.72.4.1549 ◽

1992 ◽

Vol 72 (4) ◽

pp. 1549-1556 ◽

Cited By ~ 7

Author(s):

H. Tanaka ◽

J. D. Bradley ◽

L. J. Baudendistel ◽

T. E. Dahms

Keyword(s):

Reactive Oxygen Species ◽

Polymorphonuclear Leukocytes ◽

Reactive Oxygen ◽

Cyclooxygenase Inhibitors ◽

Oxygen Species ◽

Chemotactic Peptide ◽

Middle Segment ◽

Pulmonary Vasoconstriction ◽

Lipoxygenase Products ◽

Reactive Oxygen Species Scavenger

The chemotactic peptide N-formyl-methionyl-leucyl-phenylalanine (FMLP) has been shown to constrict both bronchial and coronary vascular smooth muscle through the action of cyclooxygenase or lipoxygenase products. We observed that intravenous FMLP increased pulmonary vascular resistance (PVR) in isolated buffer-perfused rabbit lungs. FMLP increased the PVR (primarily in the middle segment of the pulmonary vascular bed) at concentrations greater than or equal to 10(-7) M. Maximum vasoconstriction occurred at 5 min and then slowly declined to a level that remained above baseline at 30 min. Tachyphylaxis was observed in response to FMLP. When polymorphonuclear leukocytes (PMNs) were added to the perfusate, FMLP caused a greater increase in PVR. PMN depletion with dimethylmyleran significantly reduced the PVR response to FMLP. Pretreatment with two dissimilar cyclooxygenase inhibitors, meclofenamate and ibuprofen, and the leukotriene synthesis blocker MK 886 had no effect on the FMLP-induced vasoconstriction. However, the reactive oxygen species scavenger catalase significantly reduced the vasoconstriction. These results suggest that FMLP induces vasoconstriction that is dependent on PMNs and mediated by reactive oxygen species with no involvement of cyclooxygenase or lipoxygenase products.

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