This preview shows page 1. Sign up to view the full content.
Unformatted text preview: arization (all of them, i think)***
some close at depolarization, open at hyperpolarize, close at depo. important in function of heart Anderson, PAV & Greenberg, RM (2001) Comp Biochem Physiol B Biochem Mol Biol 129:17-28. here's a big alpha subunit with 4 link domains. there are also one or more associated beta
subunit (2 here).each of 4 domain represent a large gush. beta subunit is associated with
outside the channel. don't have to memorize. the function of the V-Na is related to location
particular amino acid. also have certain phosphorylation site that change property of sodium
channel. Voltage-Gated Na+ Channel (Nav)
α β2 β1 Selectivity
Filter Yu & Catterall (2003)
Genome Biology 4:207 Modulation Yu & Catterall (2003)
Genome Biology 4:207 1/29/14 In the Inner Ear:
a) what is approx. value of Ek across
the apical membrane?
b) if K+ channels open in the apical
membrane, will K+ flow into or out of
c) would the current in b hyperpolarize
or depolarize the cell? Recording from Single K+ Channels we have no idea of how potassium channel work until this: patch clamping.
-patch clamping is simply to measure current flow across membrane. current refer to movement of charge through space. any time charges move
through space , this is current. current can be measured. ions (potassium) moving through aqueous solution constitute an ionic current. the scientist
took glass-micropipette (drawn with heat), making an opening at the bottom. if cell surface is clean, it will make a tight seal with clean pipette (adhesive
to each other). by chance, you might include a signal ion channel under pipette. then you stuck a wire in back, hold it to amplifier, and measure the
current that's flowing through tip of electrode. the only way current can flow through membrane is through open ion channel. this allow analyzation of
current across membrane.
-most of time there's no current flowing, at periodic interval, current is turn on very rapidly. No it's +10, the - is hashmark. the current is always same
View Full Document
This document was uploaded on 03/09/2014 for the course EXSC 301 at USC.
- Spring '09