Electrophysiology and neuronal signalling II

Question 1

Structure and function of ion channels

Answer 1

• Four subunits surrounds a transmembrane pore
• Each of four SU have 6 transmembrane segments
• S5 and 6 of all 4 SU = pore

Question 2

Summary

Answer 2

The movement of ions into and out of living cell
along their electrochemical gradients
generates electric currents across the membrane
and change membrane potential
The mechanisms of this phenomena can be studied in great detail
using whole-cell and patch-clamp electrophysiological techniques
-current clamp monitors the voltage change across the membrane
-Voltage-clamp monitors the current flow across the membrane
Voltage-gated ion channels (Na+, K+ and Ca2+) underlie
the Action Potential recorded in current clamp and neuronal
response to depolarization recorded in voltage-clamp
Action of neurotransmitters gated ion channels can be studied
using whole-cell voltage clamp recordings in isolated cells and cells in situ (in the brain slice )