Dimaprit inhibition of zymosan-stimulated beta-glucuronidase release from human granulocytes.
Histamine inhibits the in vitro release of granulocytic lysosomal beta-glucuronidase when incubated with complement activated zymosan particles and this is an H2-receptor response. The highly specific histamine H2-receptor agonist, dimaprit, also inhibits this secretory enzyme release but is less potent (-log molar ED50 6.71 with histamine vs. -log ED50 5.97 with dimaprit, p less than 0.05). No change in beta-glucuronidase release was found with the H1-agonst, 2-(2 pyridyl)-ethylamine. The antagonist activity of metiamide was similar with the two agonists (KB = 2.9 x 10(-8) M with histamine and KB = 3.6 x 10(-8) M with dimaprit). Diphenhydramine did not change the granulocyte response to either histamine or dimaprit.
D000328:Adult; D017259:Dimaprit; D005966:Glucuronidase / Q000097:blood*; D006098:Granulocytes / Q000187:drug effects* / Q000201:enzymology; D006632:Histamine / Q000494:pharmacology; D006801:Humans; D066298:In Vitro Techniques; D008247:Lysosomes / Q000187:drug effects / Q000201:enzymology; D008785:Metiamide / Q000494:pharmacology; D009504:Neutrophils / Q000187:drug effects / Q000201:enzymology; D011725:Pyridines / Q000494:pharmacology; D011968:Receptors, Histamine / Q000187:drug effects*; D011969:Receptors, Histamine H1 / Q000187:drug effects; D011970:Receptors, Histamine H2 / Q000187:drug effects*; D013890:Thiourea / Q000494:pharmacology*; D015054:Zymosan / Q000037:antagonists & inhibitors*
D011725:Pyridines; D011968:Receptors, Histamine; D011969:Receptors, Histamine H1; D011970:Receptors, Histamine H2; D008785:Metiamide; D006632:Histamine; D015054:Zymosan; C006183:2-(2-aminoethyl)pyridine; D005966:Glucuronidase; D013890:Thiourea; D017259:Dimaprit