Effects of the H2-receptor agonist dimaprit on lymphocyte responsiveness in vitro.
The histamine H2-agonist dimaprit was found to increase the response of rat spleen cells to the T-cell mitogen Concanavalin A, when present at concentrations of 10(-5) and 10(-4)M. Higher concentrations of dimaprit were cytotoxic. The enhanced response seemed to be associated with an inhibitory effect of dimaprit on T-suppressor cell activity rather than with a direct mitogen-like stimulation of lymphocyte proliferation or with an interference with monocyte/macrophage functions. The stimulatory effects of dimaprit were not reversed by the H2-receptor antagonist, cimetidine, nor by the beta-receptor antagonists metoprolol and H 35/25. Addition of the H1-receptor antagonist, mepyramine, further increased the stimulatory effect of dimaprit on lymphocyte responsiveness.
D000818:Animals; D002478:Cells, Cultured; D002927:Cimetidine / Q000494:pharmacology; D017259:Dimaprit; D004809:Ephedrine / Q000031:analogs & derivatives / Q000494:pharmacology; D005260:Female; D005944:Glucosamine / Q000378:metabolism; D066298:In Vitro Techniques; D008213:Lymphocyte Activation / Q000187:drug effects*; D008214:Lymphocytes / Q000187:drug effects*; D008790:Metoprolol / Q000494:pharmacology; D010587:Phagocytosis / Q000187:drug effects; D011738:Pyrilamine / Q000494:pharmacology; D051381:Rats; D011968:Receptors, Histamine / Q000187:drug effects*; D011970:Receptors, Histamine H2 / Q000187:drug effects*; D013601:T-Lymphocytes / Q000187:drug effects* / Q000276:immunology; D050378:T-Lymphocytes, Regulatory / Q000187:drug effects; D013890:Thiourea / Q000494:pharmacology*; D013936:Thymidine / Q000378:metabolism
D011968:Receptors, Histamine; D011970:Receptors, Histamine H2; C004380:H 35-25; D002927:Cimetidine; D008790:Metoprolol; D004809:Ephedrine; D013890:Thiourea; D011738:Pyrilamine; D005944:Glucosamine; D013936:Thymidine; D017259:Dimaprit