Module 3 - Bioelectricity Flashcards
Who is credited with the discovery of bioelectricity and when?
Luigi Galvani in 1700s
Describe galvanization
Galvani applied electric current to dissected frog legs, causing them to twitch
Describe the public experiment conducted by Giovanni Aldini (Galvani’s nephew).
Used body of executed prisoner
Minutes after execution, Aldini performed galvanization on the body, causing movements of the jaw, eyes, right hand and legs
What is electrophysiology?
Use of equipment to study bioelectricity
Who developed the differential rheotome?
Julius Bernstein in 1902
What is the differential rheotome?
Instrument used to sample membrane voltage in microsecond scale
What are the three general paradigms for electrophysiological recording?
Extracellular recording
Intracellular sharp electrodes
Whole-cell patch electrodes
What is extracellular recording?
Records voltage/ion fluxes along the outside surface of a cell
How many electrodes can be used in extracellular recording?
Single or multiple
What are intracellular sharp electrodes?
Record voltage/ion fluxes across the cell membrane
How many intracellular sharp electrodes can be used?
Single or double
What are whole-cell patch electrodes?
Record voltage/ion fluxes across the cell membrane
What is a benefit to whole-cell patch electrodes?
Large access into cell, allowing you to change the intracellular saline
What did protein engineers combine to create GCaMP calcium indicators?
- GFP
- The Ca2+ sensor protein calmodulin (CaM)
- The M13 alpha helix of the muscle protein myosin light chain kinase
What happens to GCaMP when Ca2+ levels rise?
Increases fluorescence
Describe how the GCaMP calcium indicator works.
APs cause Ca2+ influx
Ca2+ activates CaM
CaM binds the M13 helix
This pulls on the GFP protein, changing its structure
Increased GFP fluorescence