Histamine receptor on mast cells.
Mast cells isolated from the peritoneal fluid of Wistar rats were purified by centrifugation on Percoll gradient with a yield of 2x10(6) cells/ml. Cell morphology was well preserved as shown by light and electron microscopy. The mast cells capacity to bind histamine was assayed using either [3H]-histamine or histamine-ferritin conjugate as electron-opaque probe for electron microscopic examination. The [3H]-histamine binding performed at 4 degrees C in Ca2+-free phosphate-buffered saline pH 7.3 completed within 30 min was found to be specific, with an IC50 value of 0.72 +/- 0.23 nM. The data analyses by Scatchard and Hill's representations showed a KD of 0.60 +/- 0.24 nM and Bmax of 4.9 +/- 1.2 pM/10(6) cells suggesting that on mast cells the histamine receptors are restricted to the plasma membrane. According to Hill's analysis neither positive nor negative cooperativity (n = 1.06) appeared to be involved in the specific histamine-receptor binding. Competition experiments with 4-methylhistamine and SK&F 93479, revealed that mast cells express H2-histamine receptors. At electron microscopic level, the histamine-ferritin conjugate interstitially injected in the hamster cheek pouch was localized on the mast cell membrane.
Antohe
F
F
Institute of Cellular Biology and Pathology, Bucharest, Romania.
Dobrila
L N
LN
Heltianu
C
C
D000818:Animals; D001667:Binding, Competitive; D002478:Cells, Cultured; D002610:Cheek; D006224:Cricetinae; D008297:Male; D008407:Mast Cells / Q000032:analysis*; D008854:Microscopy, Electron; D051381:Rats; D011919:Rats, Inbred Strains; D011968:Receptors, Histamine / Q000032:analysis* / Q000378:metabolism; D013696:Temperature
D011968:Receptors, Histamine