RESUMO
Calcitonin gene-related peptide (CGRP) is a sensory neuropeptide with inflammatory and immunoregulatory activities. Its role in B lymphocyte development was investigated using a pre-B cell colony-forming assay. Physiological concentrations of CGRP inhibited pre-B cell responses to interleukin-7 (IL-7). Inhibition was specific in that it was blocked by the CGRP antagonist CGRP8-37. Adrenomedulin, substance P, and calcitonin had no effect on B cell precursor responses. Similar responses were observed with B220+/IgM- B cell precursors. Inhibition of IL-7 responses in B220+/IgM- cells suggests that CGRP has a direct effect on B cell precursors. Studies with cultured bone marrow-adherent cells found that CGRP also has an indirect effect on IL-7 responses. Cultured bone marrow-adherent cells were treated with CGRP for 24 h, and anti-CGRP was added to the supernatants to neutralize CGRP. Concentrations of CGRP as low as 0.01 nM induced a factor that inhibited colony formation. In contrast, CGRP did not induce an inhibitory factor in cultured bone marrow macrophages, suggesting that CGRP induces an inhibitory factor in some adherent cell other than macrophages. The results show that CGRP has both direct and indirect effects on developing B cells and support a role for CGRP as an inhibitor of early B cell development.
Assuntos
Linfócitos B/citologia , Linfócitos B/imunologia , Peptídeo Relacionado com Gene de Calcitonina/farmacologia , Células-Tronco Hematopoéticas/citologia , Interleucina-7/farmacologia , Adrenomedulina , Animais , Linfócitos B/efeitos dos fármacos , Células da Medula Óssea/citologia , Células da Medula Óssea/fisiologia , Calcitonina/farmacologia , Adesão Celular , Células Cultivadas , Ensaio de Unidades Formadoras de Colônias , Feminino , Células-Tronco Hematopoéticas/efeitos dos fármacos , Interleucina-7/antagonistas & inibidores , Macrófagos/efeitos dos fármacos , Macrófagos/imunologia , Masculino , Camundongos , Camundongos Endogâmicos BALB C , Fragmentos de Peptídeos/farmacologia , Peptídeos/farmacologia , Substância P/farmacologiaRESUMO
Research investigating the application of pressure-cycled bubble chambers to fast neutron detection is described. Experiments with a Halon-filled chamber showed clear sensitivity to an AmBe neutron source and insensitivity to a (137)Cs gamma source. Bubble formation was documented using high-speed photography, and a ceramic piezo-electric transducer element registered the acoustic signature of bubble formation. In a second set of experiments, the bubble nucleation response of a Freon-134a chamber to an AmBe neutron source was documented with high-speed photography.
RESUMO
Calcitonin gene-related peptide (CGRP) is a sensory neuropeptide with inflammatory and immunoregulatory properties. CGRP inhibits IL-7 responses by B cell precursors by direct and indirect mechanisms. We recently found that CGRP induces IL-6 and TNF-alpha in long-term bone marrow cultures and that IL-6 and TNF-alpha also inhibit IL-7 responses. Because these are heterogeneous cultures, it was not clear which cells produced IL-6 and TNF-alpha. To determine whether bone marrow-derived macrophages (BMDM) were the source, we did studies to determine whether BMDMs express mRNAs for CGRP receptors and whether CGRP induces c-fos, IL-6, and TNF-alpha mRNA. We found that BMDMs express mRNAs for CRLR and RAMP1, the minimal components for CGRP receptors. CGRP also stimulated dose- and time-dependent increases in c-fos and IL-6. In contrast, CGRP did not induce TNF-alpha in BMDMs. These results suggest that BMDMs are a source of CGRP-induced IL-6 in bone marrow.