Increment of calcium-activated and delayed rectifier potassium current by hyposmotic swelling in gastric antral circular myocytes of guinea pig
Abstract
Aim: To observe the effect of hyposmotic swelling on calcium-activated potassium current [IKCa] and delayed rectifier potassium current [IKV] in gastric antral circular myocytes of guinea pig.
Methods: The whole cell patch-clamp technique was used, and the myocytes were isolated by collagenase. Cells were swelled by the hyposmotic solution (200 Osmmol/kg).
Results: The hyposmotic solution markedly increased IKCa and IKV. The increase of IKCa was markedly inhibited by tetrathylammonium (TEA) 4 mmol/L and charybdotoxin (ChTX) 200 nmol/L. The increase of IKV was incompletely blocked by TEA and completely blocked by 4-aminopyridine (4-AP) 10 mmol/L. There was no significant difference between the amplitudes of the increase of IKCa and IKV (P < 0.05). IKCa increased (17.0 +/- 4.8) s after the cells were perfused with the hyposmotic solution, whereas IKV increased (30.7 +/- 13.7) s after the cells exposed to the hyposmotic solution. There was significant difference between the latency of IKCa and IKV (P < 0.05).
Conclusion: Hyposmotic swelling increased both IKCa and IKV, and the increment was likely related to the cell volume regulation.
Keywords:
Methods: The whole cell patch-clamp technique was used, and the myocytes were isolated by collagenase. Cells were swelled by the hyposmotic solution (200 Osmmol/kg).
Results: The hyposmotic solution markedly increased IKCa and IKV. The increase of IKCa was markedly inhibited by tetrathylammonium (TEA) 4 mmol/L and charybdotoxin (ChTX) 200 nmol/L. The increase of IKV was incompletely blocked by TEA and completely blocked by 4-aminopyridine (4-AP) 10 mmol/L. There was no significant difference between the amplitudes of the increase of IKCa and IKV (P < 0.05). IKCa increased (17.0 +/- 4.8) s after the cells were perfused with the hyposmotic solution, whereas IKV increased (30.7 +/- 13.7) s after the cells exposed to the hyposmotic solution. There was significant difference between the latency of IKCa and IKV (P < 0.05).
Conclusion: Hyposmotic swelling increased both IKCa and IKV, and the increment was likely related to the cell volume regulation.