Prostaglandin H synthetase activates xenobiotics into free radicals: histamine release and biochemical characteristics.
In isolated rat serosal mast cells, studies with the fluorescent Ca2+ indicator, quin 2, and with [3H]-myoinositol to label endogenous polyphosphoinositides have established that an increase in cytosol Ca2+ levels was obligatory for histamine release by free radicals. No substantial breakdown of phosphatidylinositol and related polyphosphoinositides was associated with generation of the Ca2+ signal and histamine release, suggesting that the release of histamine by free radicals entails different pathways than the calcium-mobilizing receptors linked to polyphosphoinositides as second messengers.
Masini
E
E
Department of Preclinical and Clinical Pharmacology, University of Florence, Italy.
Giannella
E
E
Palmerani
B
B
Pistelli
A
A
Gambassi
F
F
Mannaioni
P F
PF
D000818:Animals; D001711:Biotransformation; D002118:Calcium / Q000502:physiology*; D005609:Free Radicals; D006636:Histamine Release; D066298:In Vitro Techniques; D008407:Mast Cells / Q000502:physiology; D010100:Oxygen / Q000494:pharmacology*; D010716:Phosphatidylinositols / Q000502:physiology*; D011451:Prostaglandin-Endoperoxide Synthases / Q000378:metabolism; D051381:Rats; D015262:Xenobiotics / Q000378:metabolism
D005609:Free Radicals; D010716:Phosphatidylinositols; D015262:Xenobiotics; D011451:Prostaglandin-Endoperoxide Synthases; D010100:Oxygen; D002118:Calcium