Induction of two K+ currents by complement component C5a in mouse macrophages.
Puff application of complement component C5a (5 x 10(-8) M) onto peritoneal macrophages from thioglycollate-stimulated mice induced two kinds of outward current at a holding potential of -68 mV, a slowly-rising sustained outward current and a spike-like transient outward current. Quinidine (2 x 10(-4) M) and tetraethylammonium (10(-2) M) partially suppressed both types of outward current. Charybdotoxin (2 x 10(-6) M) markedly suppressed the spike-like outward current. Reversal potentials in bath solutions of different external K+ concentrations were dependent only on K+ concentrations. The transient current was not suppressed in Ca(2+)-free EGTA-containing solution, but was completely abolished in BAPTA-containing solution. One kind of single channel responding to C5a, which has a single-channel conductance of 29 pS, was recorded from cell-attached patches. These results suggest that C5a activates a Ca(2+)-dependent and another type of K+ current.
Ichinose
M
M
Department of Physiology, Shimane Medical University, Izumo, Japan.
Hara
N
N
Sawada
M
M
Maeno
T
T
D000818:Animals; D002118:Calcium / Q000378:metabolism; D018999:Charybdotoxin; D015936:Complement C5a / Q000037:antagonists & inhibitors / Q000502:physiology*; D015232:Dinoprostone / Q000494:pharmacology; D004533:Egtazic Acid / Q000031:analogs & derivatives / Q000494:pharmacology; D004594:Electrophysiology; D008264:Macrophages / Q000378:metabolism*; D051379:Mice; D008809:Mice, Inbred C3H; D011188:Potassium / Q000378:metabolism*; D011802:Quinidine / Q000494:pharmacology; D012604:Scorpion Venoms / Q000494:pharmacology; D019789:Tetraethylammonium; D013757:Tetraethylammonium Compounds / Q000494:pharmacology
D012604:Scorpion Venoms; D013757:Tetraethylammonium Compounds; D018999:Charybdotoxin; D004533:Egtazic Acid; D019789:Tetraethylammonium; D015936:Complement C5a; D011802:Quinidine; C025603:1,2-bis(2-aminophenoxy)ethane-N,N,N',N'-tetraacetic acid; D015232:Dinoprostone; D011188:Potassium; D002118:Calcium