EFFECTS OF DIFFERENT SUBTYPES OF HISTAMINE-RECEPTORS ON PROLIFERATIONAND DIFFERENTIATION OF MURINE COLONY-FORMING UNIT GRANULOCYTE-MACROPHAGE AND COLONY-FORMING UNIT MEGAKARYOCYTE

Objective To investigate the function and characteristics of histamine receptors on the hemopoietic progenitor cells. Methods BDF1 mice (bot h male and female), inbred at our university, aged 8-12 weeks, weighin g 20-24 g, were used in this study. Bone marrow cells were incubated f or 1 hour at 37 degrees C with 2-AT (H-1 receptor agonist) or impromid ine (H-2 receptor agonist) alone, or in combination with the antagonis ts pyrilamine or cimetidine respectively. Control experiment was perfo rmed in Dulbecco' s modified Eagle' s Medium (DMEM) alone. Cells treat ed with different drugs were performed by colony forming unit-granuloc yte-macrophage (CFU-GM) and colony forming unit-megakaryocyte (CFU-Meg ) assay. Results When bone marrow cells were treated with 10(-8) mol/L to 10(-5) mol/L of 2-thiazolylethylamine (2-AT) which had no influenc e on CFU-GM and CFU-Meg proliferation, 10(-8) mol/L to 10(-5) mol/L of impromidine could increase the number of CFU-GM and CFU-Meg colonies. The effects of H-2 receptor agonists on CFU-GM, CFU-Meg could be anta gonized by H-1 receptor agonist. Conclusions Our findings suggest the existence of histamine H-1 and H-2 receptors on the hemopoietic progen itor cells and the antagonism between two different histamine receptor subtypes on the proliferation of CFU-GM and CFU-Meg.