Ion channels Flashcards
Ohms law
V=I*R
V=voltage - volts mV
I=current - amperes pA
R=resistnace - ohms Mtheta
two methods of measurement of the ionic currents involved in cellular functions
electrophysiological recording
- patch clamp
- planar lipid bilayer techniques
patch clamp
= direct recording of ionic currents from cell surface ion channels
planar lipid bilayer techniques
= direct recording of ionic currents from intracellular ion channels
circuit order
thing amplifier digitiser computer graph
What kinds of things open a channel
voltage
ligand
stretch
light
ligand
neurotransmitter binds and activates from outside cell
stretch
mechanosensitive channels
light
channelrhodopsin
equation for the probability of channel gating
Popen = Topen / Ttotal
What information can we obtain from single channel recordings?
- signal channel conductance = how good a channel is at letting current through
- What ions flow through the channel
- inhibitors of the channel
macroscopic ionic current
is equal to the product of the number of channels within the membrane area, the unitary current and the probability of channel opening
inhibitor of Na+ channel
tetrodotoxin
inhibitor of K+ channel
tetraethylammonium
symptoms of an arrhythmia
dizzy spells
fainting episodes
sudden cardiac death
