Repetitive deformation and pressure activate small bowel and colonic mucosal tyrosine kinase activity in vivo

Physical forces like deformation and pressure modulate signaling and phenotype in cultured cells. However, it is more difficult to establish that such phenomena occur in vivo. We studied the effects of 0 to 10 minutes of rhythmic distension with an isotonic electrolyte and polyethylene glycol solution to 30 cm H(2)O pressure on defunctionalized small and large bowel segments in adult male Sprague Dawley rats. Mucosa was harvested at 0, 1, and 10 minutes and assayed for tyrosine kinase activity. Rhythmic distension caused a time-dependent increase in colonic mucosal tyrosine kinase activity, which was statistically significant at 10 minutes (140% +/- 41% increase, n = 5, P <.05). Small bowel tyrosine kinase activity was markedly lower than that observed in the colon, but achieved a statistically significant increase at 5 minutes after initiation of rhythmic distension. (115% +/- 44% increase, n = 5, P <.05).