Sources of calcium in agonist-induced contraction of rat distal colon smooth muscle in vitro

Figure 5 Contribution of Ca²⁺ release from SR stores and Ca²⁺ influx via CCE in ACh-induced distal colon contraction. Aa: In the presence of atropine, restoration of extracellular Ca²⁺ induced contraction, most likely due to Ca²⁺ influx via CCE; Ab: VOCC blocker verapamil (5 &mgr;mol/L) negligibly affected CCE-mediated contraction in the presence of atropine; B: Summarized data showing that CCE-mediated contraction is about 0.46-fold greater than the contraction induced by SR Ca²⁺ release in ACh-induced rat distal colon contraction. ^bP < 0.001 vs Ca²⁺ release.