...., E.S.M.C., M.A.C., D.M.P., A.V.M.C. and J.F. wrote paper. Competing interests The authors declare no competing financial interests. 17 10 2013 13 1 2014 © 2014. Published by The Company of Biologists Ltd 2014 Intestinal physiology Calcium regulation Bicarbonate...

... ; Shadwick and Pollock, 1988 ). They are stiffened by subsequent restoration of normal calcium concentrations. These experimental results are consistent with two distinct hypotheses. In the ‘extracellular calcium regulation’ hypothesis, the neurosecretory cells control the mechanical properties of the tissue...