Class Flashcards
What is the membrane treated as in the Voltage Clamp Experiment?
It is treated as an identical patch of membrane
What did the Voltage Clamp Experiments allow?
Allowed the membrane potential to be manipulated so that voltage across membrane could be measured
What did Hodgkin and Huxley hypothesize?
Action potentials must be mediated by ion channels in the membrane.
What did Sakmann and Neher do?
Invented a technique where currents could be measured through a single channel called the Patch Clamp technique.
How does Patch Clamp work?
Took glass capillary tubing, put it on the membrane, and the membrane was able to stick to the glass and create a tight seal, and the currents could then be measured in the place where the glass stuck to the membrane.
What did Patch Clamp measure?
The current flowing in and out of a single channel of the membrane.
What did Sakmann and Neher discover?
Ion channels have states where they are open and states where they are closed (or just not let ions through).
What did Sakmann and Neher hypothesize?
The aggregate of all the currents through the membrane channels is the macroscopic current that flows into and out of the membrane.
What types of Patch Clamp techniques are there?
Whole cell recording, inside-out recording and outside-out recording (useful for studying neurotransmitter-gated ion channels)
What are the tasks that ion channels have to perform?
They need to have a pore, they need to be gated, they need to be selective, and they need to have a high permeability.
What makes it difficult to form a pore that lets ions through?
Pores need to be hydrophilic, proteins need to be lipophilic.
What does tetrodotoxin do?
It binds to sodium channels and inactivates them.
