Characterization of functional histamine H1 receptors on a cultured smooth muscle cell line.
Cultured cells of the smooth muscle line DDT1MF-2, which was derived from a hamster vas deferens tumor, expressed histamine H1-type receptors and responded biochemically and functionally to H1-specific stimulation. The H1-receptor antagonist [3H]-pyrilamine bound specifically to 9.7 x 10(6) sites/DDT1MF-2 cell with a dissociation constant (Kd) of 219 nM. The addition of histamine to suspensions of fura-2-loaded DDT1MF-2 cells elicited a rapid, transient, and stimulus concentration-dependent increase in the intracellular concentration of Ca2+ with an EC50 of 3 x 10(-5) M, which demonstrated H1 receptor specificity. Moreover, in order to evaluate in vitro contractile response of individual DDT1MF-2 cells, the degree of intracellular actin polymerization was quantified by a DNase inhibition assay. The percentage of nonpolymerized or G-actin in DDT1MF-2 cells was reduced in a histamine concentration-dependent manner with an EC50 of 1 x 10(-5) M and H1 receptor specificity. Histamine-induced actin polymerization was accompanied by changes in cell shape that were consistent with cellular contraction, as assessed by flow cytometry. The H1-type receptors of cultured DDT1MF-2 cells thus couple histamine stimulation to a variety of functional responses of smooth muscle cells.
Mitsuhashi
M
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Howard Hughes Medical Institute Laboratories, University of California Medical Center, San Francisco 94143-0724.
Payan
D G
DG
D000199:Actins / Q000378:metabolism; D000818:Animals; D002118:Calcium / Q000378:metabolism; D002460:Cell Line; D006224:Cricetinae; D003851:Deoxyribonucleases / Q000037:antagonists & inhibitors; D005434:Flow Cytometry; D006632:Histamine / Q000378:metabolism* / Q000494:pharmacology; D008024:Ligands; D008297:Male; D009119:Muscle Contraction; D009130:Muscle, Smooth / Q000378:metabolism*; D011108:Polymers; D011738:Pyrilamine / Q000378:metabolism; D011968:Receptors, Histamine / Q000032:analysis*; D011969:Receptors, Histamine H1 / Q000032:analysis* / Q000378:metabolism; D012984:Software; D014649:Vas Deferens / Q000378:metabolism
D000199:Actins; D008024:Ligands; D011108:Polymers; D011968:Receptors, Histamine; D011969:Receptors, Histamine H1; D006632:Histamine; D003851:Deoxyribonucleases; D011738:Pyrilamine; D002118:Calcium