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1. Potassium channel

1. Potassium channel. Function: 1.shape action potentials and set the resting membrane potential 2. maintaining vascular tone 3. secretion of hormones 4. ion transport. Types. Voltage-gated potassium channel Inwardly rectifying potassium channel

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1. Potassium channel

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  1. 1. Potassium channel • Function: 1.shape action potentials and set the resting membrane potential 2. maintaining vascular tone 3. secretion of hormones 4. ion transport

  2. Types • Voltage-gated potassium channel • Inwardly rectifying potassium channel • resting potassium channels" or "leak channels • Calcium-activated potassium channel

  3. 6TM: The voltage-gated K+ channels Kv, KCNQ, Kca2+

  4. A-type currrent M-current

  5. 2-TM. The inward rectifier K+ KIR1.x, KIR2.x, KIR3.x, KIR4.x, KIR5.x, KIR6.x and KIR7.x

  6. 4-TM. Sensitive to halothane,insensitive to TEA and 4-AP Regulate cell volume

  7. 2. Cell recording solutions and Protocol for Ca2+、Na+、K+

  8. (1) Calcium channels and Protocol

  9. Protocol 激活曲线

  10. 失活曲线 稳态失活曲线

  11. 失活后再激活曲线

  12. （2）Sodium channel

  13. Protocol

  14. （3）Potassium channel

  15. ① Inwardly rectifying potassium channel(KIR) 激活方案

  16. ②The delayed rectifier current (IK) • largely responsible for repolarization and consists of two components namely IKs and IKr.

  17. Voltage-Time dependent activation IKtail

  18. Time dependent activation IKtail

  19. 豚鼠心室肌细胞

  20. ③ KATP

  21. KATP

  22. Smooth muscle cells βcell

  23. Whole cell recording, With ATP and GDP in the pipette solution, Vh-60 inside-out patch. The pipette potential is -100 mV

  24. inside-out patch

  25. Why Vh-60? Answer:minimize Kca Inside out-recording(-100mv) Bath solution (for the intracellular side of the membrane) included (mM): KCl 120, KOH 20, MgCl2 1, EGTA 5, Hepes 10, glucose 5, Na2ATP 0.3, and MgADP 0.5 (pH=7.2); while pipette solution (for the extracellular side of the membrane) contained (mM): KCl 140, MgCl2 2, EGTA 2, glucose 10, and Hepes 10 (pH=7.4).

  26. Whole cell-recording The bath solution contained (mM): NaCl 140, KCl 5.4, MgCl2 1.2, HEPES 10, EGTA 2, glucose 10 (pH adjusted to 7.4 with NaOH). The pipette solution comprised (mM): KCl 140, MgCl2 1, EGTA 10, HEPES 10, glucose 5, Na2ATP 0.3, and MgADP 0.5 (pH=7.2)

  27. The membrane potential recording The bath solution contained (mM): NaCl 140, KCl 5.4, MgCl2 1.2, HEPES 10, EGTA 2, glucose 10 (pH adjusted to 7.4 with NaOH). The pipette solution comprised (mM): KCl 140, MgCl2 1, EGTA 10, HEPES 10, glucose 5, nystatin 250 μg/ml

  28. ④ IK,M------(KCNQ2-KCNQ3) • the M-current characterized as a low-threshold, voltage-gated K+ current that is active around the resting membrane-potential and constitutes an important regulator of neuronal excitability a voltage-and time-dependent, low-threshold, slowly activating current.

  29. IKM tail Traditional M-current voltage-clamp protocol: holding potential was -30 mV; step potentials were -40 to -80 mV Activation from a holding potential of -60 mV in 5 mV increments.

  30. 0.3 nA, 200-ms current-pulse injection M- current

  31. ⑤Transient inactivating A-type current (IA) Predominant K+ current in many mature neurons that is initially activated at the subthreshold range of membrane potential and deactivated during depolarizing pulses of duration.

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