Figure 7.

Ca²⁺ imaging in human colonic muscles. (A) In a muscle preparation, 4 PDGFRα⁺ cells generated developed asynchronous spontaneous Ca²⁺ transients independently from each other. (B) In a preparation where PDGFRα⁺ cells generated asynchronous spontaneous Ca²⁺ transients (b), ICC exhibited synchronous spontaneous Ca²⁺ transients within their cluster (c). PDGFRα⁺ cells responded to MRS2365 100 nmol/L but not ACh 1 μmol/L (arrows in a and b), whereas ICC responded to ACh 1 μmol/L but not MRS2365 100 nmol/L (arrowheads in a and c). Graph of Ca²⁺ signals picked in each of cells pointed by color arrows or arrowheads in (a) were depicted in (b) and (c) in the same color as that of arrow or arrowhead. (C) In a preparation where PDGFRα⁺ cells generated asynchronous spontaneous Ca²⁺ transients, ADP 100 μmol/L evoked increases in basal Ca²⁺ level (a and b). (D) In a preparation where PDGFRα⁺ cells generated asynchronous spontaneous Ca²⁺ transients, EFS (20 Hz for 1 second) triggered synchronous increases in basal Ca²⁺ level (red arrowheads in D). MRS2500 500 nmol/L largely suppressed EFS-induced Ca²⁺ transients and also prevented generation of spontaneous Ca²⁺ transients. (E) In a preparation where PE 10 μmol/L caused increases in basal Ca²⁺ level associated with superimposed Ca²⁺ oscillations in several cells (middle panel in a and b), MRS2365 100 nmol/L evoked sustained increases in basal Ca²⁺ level in the same cells (right panel in a and c). Graph of Ca²⁺ signals picked in each of color circles in (a) were depicted in (b) and (c) in the same color as that of the circle.