In vivo inhibition of polymyxin B-induced hypotension: evidence of beta-adrenergic inhibitory activity on rat mast cells.
In vitro, rat mast cells show a dose-inhibition profile when stimulated with compound 48/80 in the presence of isoprenaline. Isoprenaline-induced inhibition is stereoselective at low concentrations, being greater on pleural mast cells. In vitro, polymyxin B (0.02-0.05 mg/kg) induces a marked hypotension and slow heart rate, but not tachyphylaxis. Both effects were not suppressed in the presence of isoprenaline (with short half-life in vivo), but orciprenaline does induce a clear inhibition of Polymyxin B-induced hypotension, which correlates well with heart rate.
D000818:Animals; D001794:Blood Pressure / Q000187:drug effects; D006339:Heart Rate / Q000187:drug effects; D006636:Histamine Release / Q000187:drug effects; D007022:Hypotension / Q000139:chemically induced / Q000517:prevention & control*; D066298:In Vitro Techniques; D007545:Isoproterenol / Q000494:pharmacology; D008297:Male; D008407:Mast Cells / Q000187:drug effects* / Q000502:physiology; D011112:Polymyxin B / Q000633:toxicity*; D011113:Polymyxins / Q000633:toxicity*; D051381:Rats; D011919:Rats, Inbred Strains; D011943:Receptors, Adrenergic, beta / Q000187:drug effects* / Q000502:physiology
D011113:Polymyxins; D011943:Receptors, Adrenergic, beta; D011112:Polymyxin B; D007545:Isoproterenol