“…activity of various signaling molecules that regulate smooth muscle contraction and relaxation (Akiho et al, 2002;Shi et al, 2003;Cao et al, 2004;Jin et al, 2004;Salinthone et al, 2004;Singer et al, 2004;Shi and Sarna, 2005;Zhao et al, 2005Zhao et al, , 2006Khan and Collins, 2006;Ohama et al, 2007;Ihara et al, 2012;Shea-Donohue et al, 2012;Yang et al, 2013). Previous studies have identified that signaling pathways that mediate initial and sustained contraction in intestinal longitudinal muscle are distinct from those in circular muscle (Grider and Makhlouf, 1988;Murthy, 2006).…”