1. In vitro activation of murine DRG neurons by CGRP-mediated mucosal mast cell degranulation
- Author
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L. Van Nassauw, Alfons B.A. Kroese, Hugh R. P. Miller, A. De Laet, Jean-Pierre Timmermans, Jeremy K. Brown, P.P. Van Bogaert, F De Jonge, and University of Groningen
- Subjects
Male ,cultured mucosal mast cells ,Physiology ,Substance P ,Cell Degranulation ,DE-GRANULATION ,chemistry.chemical_compound ,cultured dorsal root ganglia neurons ,Ganglia, Spinal ,Mast Cells ,Intestinal Mucosa ,Receptor ,Cells, Cultured ,Neurons ,Gastroenterology ,Degranulation ,Mast cell ,Body Fluids ,RECEPTORS ,calcium imaging ,medicine.anatomical_structure ,CYTOPLASMIC VESICLES ,EXPRESSION ,mast cell juice ,Calcitonin Gene-Related Peptide ,Neuropeptide ,Calcitonin gene-related peptide ,Biology ,TRICHINELLA-SPIRALIS ,Downregulation and upregulation ,Physiology (medical) ,medicine ,Animals ,p-Methoxy-N-methylphenethylamine ,Hepatology ,Osmolar Concentration ,Intracellular Membranes ,electrophysiology ,SUBSTANCE-P ,Molecular biology ,MICE ,SUBMUCOUS NEURONS ,nervous system ,chemistry ,Immunology ,GUINEA-PIG COLON ,HISTAMINE-RELEASE ,Calcium ,Neuron - Abstract
Upregulation of CGRP-immunoreactive (IR) primary afferent nerve fibers accompanied by mastocytosis is characteristic for the Schistosoma mansoni-infected murine ileum. These mucosal mast cells (MMC) and CGRP-IR fibers, which originate from dorsal root (DRG) and nodose ganglia, are found in close apposition. We examined interactions between primary cultured MMC and CGRP-IR DRG neurons in vitro by confocal recording of intracellular Ca2+concentration ([Ca2+]i). The degranulatory EC50for the mast cell secretagogue compound 48/80 (C48/80; 10 μg/ml) and the neuropeptides CGRP (2.10−8M) and substance P (SP; 3.10−8M) were determined by measurement of extracellular release of the granule chymase, mouse mast cell protease-1. Application of C48/80 (10 μg/ml) and CGRP and SP (both 10−7M) to Fluo-4-loaded MMC induced a transient rise in [Ca2+]iafter a lag time, indicative of mast cell degranulation and/or secretion. The CGRP response could be completely blocked by pertussis toxin (2 μg/ml), indicating involvement of Giproteins. Application of MMC juice, obtained by C48/80 degranulation of MMC, to Fluo-4-loaded DRG neurons induced in all neurons a rise in [Ca2+]i, indicative of activation. Degranulation of MMC by C48/80 in culture dishes containing Fluo-4-loaded DRG neurons also caused activation of the DRG neurons. In conclusion, these results demonstrate a bidirectional cross-talk between cultured MMC and CGRP-IR DRG neurons in vitro. This indicates that such a communication may be the functional relevance for the close apposition between MMC and CGRP-IR nerve fibers in vivo.
- Published
- 2004