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. Author manuscript; available in PMC: 2014 Mar 26.
Published in final edited form as: Compr Physiol. 2013 Apr;3(2):667–692. doi: 10.1002/cphy.c110014

Figure 12.

Figure 12

Whole-cell currents recorded from SAN cells of guinea-pig heart. (A) An example of single SAN cells (arrows) isolated from the SAN region of guinea pig heart by enzymatic dispersion. (B) Whole-cell currents recorded from SAN cells. When cations (Na+ and K+) were included in the extracellular solutions, inward currents were slowly activated upon hyperpolarization under isotonic (a) conditions. Exposure of the same cell to hypotonic extracellular solution caused cell swelling and an increase in the inward current amplitude (b). The difference current caused by hypotonic cell swelling is shown in panel e. Subsequent replacement of 20 mmol/L of NaCl with CsCl caused a significant inhibition of the inward current (c). The Cs+-sensitive current is shown in panel f. Subsequent addition of 0.2 mmol/L of Cd2+ to the hypotonic solution caused an inhibition of the inward current (d). The Cd2+-sensitive currents are shown in panel g (89).