Authors: Claire Jarrousse Nadege Lods Francoise Michel Jean Pierre Bali Richard Magous
Publish Date: 2004/03/05
Volume: 316, Issue: 2, Pages: 221-232
Abstract
In the digestive tract the transit of ingested food induces a local contractionrelaxation reflex of which the smooth muscle cell SMC represents the functional unit Although freshly isolated SMCs have been extensively used for in vitro studies in specific cases cultured cells appear necessary Because conventionally cultured SMCs lose their contractile properties we have developed 1 differentiated contractile rabbit gastric SMCs Dstim cells cultured in a medium supplemented with insulin and 2 proliferative dedifferentiated rabbit gastric SMCs Pstim cells cultured in a medium supplemented with insulin fetal serum EGF and bFGF The proliferative index was 5±4 and 82±10 respectively for Dstim and Pstim cells Expression of SMmyosin heavy chain was observed in 90 of Dstim cells whereas it was progressively lost in Pstim cells Carbachol 1–100 nM glicentin 2 nM and gastrin17 100 nM induced contraction of Dstim cells cultured for 3 or 6 days whereas they did not induce the contraction of Pstim cells in contrast gastrin17 10 nM was able to stimulate DNA synthesis 186±009fold increase in Pstim cells The coupling of muscarinic receptors to intracellular transduction pathways was evaluated in Dstim cells at day 3 carbachol 100 nM induced a twofold increase in the production of inositol tritetraphosphates in parallel a phosphorylation of ERK MAP kinases occurred within 1 min of carbachol stimulation In conclusion cultured functional myocytes derived from mature tissue may be used for longterm studies concerning the events coupled either to proliferation or to motility regulation of differentiated SMCs due to the activation of Gproteincoupled receptors
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