NROB60H3 Chapter Notes - Chapter 4: Voltage-Gated Potassium Channel, Patch Clamp, Potassium Channel
Document Summary
Membrane potential (vm) determined by inserting a microelectrode in cell- voltmeter reads a potential difference. During ap: oscilloscope records the voltage that changes over time [graph= vm vs time] (2 milliseconds) Overshoot= inside of neuron is + charged in respect to outside (peak of 40 mv) Falling phase= rapid repolarization until the membrane is more than resting. If the depolarization (generaor potential) reaches a critical level (threshold)= ap will generate. Interneurons= ap caused naturally by nt released by other neurons. Injecting electrical current through a microelectrode= ap caused mechanically. Pass continuous depolarizing current into a neuron through a microelectrode= many ap generated in succession. But rate of ap generation depends on magnitude of the continuous depolarizing current. Firing frequency reflects the magnitude of the depolarizing current. Pass current to depolarizing just to threshold= ap"s generated at 1 hz (1 per second) Crank it up= rate of ap"s ^ to 50 hz.
