Chapter 4 Flashcards
Explain patch clamping
uses a microelectrode to study ion currents
cell attached patch clamping
- can measure current while changing extracellular conditions
- recording effects of in-tact signaling pathways
whole cell recording patch clamping
- continuity of broken cell membrane and electrode
- can introduce substances into the cell and measure whole cell currents
inside out patch clamping
- good for channels controlled by intracellular conditions like cyclic nucleotides
- can manipulate inside contents
outside out patch clamping
- most difficult
- allows generation of dose-responsive curve
activation gate
- rapid movement
- closed below threshold & opens during depolarization
- closes during repolarization
inactivation gate
- slower movement
- open below threshold and slower closing in response to depolarization
- opens during repolarization
How do ion channels open?
- response to ions, like Na+ SCN gene, Ca+ CACNA gene, or Cl- CLCN gene
rectifier
ion channel that is specialized to conduct current in one direction
Ligand gated channels
ionotropic receptors controlled by neurotransmitters (ex: cyclic-nucleotide gated channels)
Acid sensing ion channels
open in response to H+ and are permeable to Na+
Mechanosensitive channels
open from stretch or pressure (ex: Peizo nonselective channels)
Bacterial K+ channel
- pH gated
- four subunits connected by a pore loop
Voltage gated Cl- channel
heterodimer that helps maintain electrical stability of the neuron
Thermosensitive channel
activated by temperature conformational change (that displaces mb lipids)
Active transporters
- transport at least one ion against its concentration gradient
- slower than channel mediated channels
What happens if the Na+/K+ ATPase is blocked?
No immediate short term effect, but the concentration gradient will not be maintained
Cotransport
- active, all molecules moving in the same direction
- often Na+ (moving into the cell)
Antiporters
- active, one moves into the cell and one moves out
- ex: Na+/Ca+ exchanger
