Effect of TMB-8 on histamine release from isolated rat mast cells.
TMB-8 was capable of complete inhibition of the histamine release induced by antigen, compound 48/80, and the ionophore A23187 (2 microM). The effective concentrations for 50% inhibition (IC50) were 1.2 X 10(-4) M for antigen, 1.6 X 10(-4) M for compound 48/80 both in the absence and in the presence of calcium, and 0.7 X 10(-4) M for the ionophore. The inhibitory action was not affected by increased calcium concentration in the medium from 1 to 2m M. The presence of glucose in the medium counteracted the inhibition by TMB-8 and, for low concentrations of the ionophore (0.25 microM), TMB-8 caused a pronounced enhancement of the histamine release. Our results indicate that TMB-8 primarily exerts its effects by interference with oxidative metabolism rather than by affecting the intracellular calcium availability.
Grossman
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D000818:Animals; D000001:Calcimycin / Q000494:pharmacology; D002118:Calcium / Q000378:metabolism; D002121:Calcium Channel Blockers / Q000494:pharmacology*; D004305:Dose-Response Relationship, Drug; D005707:Gallic Acid / Q000031:analogs & derivatives* / Q000494:pharmacology; D005947:Glucose / Q000494:pharmacology; D006636:Histamine Release / Q000187:drug effects*; D066298:In Vitro Techniques; D008297:Male; D008407:Mast Cells / Q000187:drug effects / Q000378:metabolism*; D051381:Rats; D011919:Rats, Inbred Strains; D003189:p-Methoxy-N-methylphenethylamine / Q000494:pharmacology
D002121:Calcium Channel Blockers; D000001:Calcimycin; D003189:p-Methoxy-N-methylphenethylamine; C006014:8-(N,N-diethylamino)octyl-3,4,5-trimethoxybenzoate; D005707:Gallic Acid; D005947:Glucose; D002118:Calcium