Lecture 14: Electrophys Flashcards
Ohm’s Law
V = I x R
What is the best example of a drug that targets ion channels? What do they do to which channels?
Local anesthetics; block VG-Na+ channels
Describe two types of neuronal firing
Tonic (pacemaker), associated with HCN channles and burst firing, associated with greater NT release
What happens when an AP reaches a nerve terminal?
Activation of VG-Ca2+ channels
Why do muscle cells contract in response to all presynaptic APs? (2)
1) High probability of ACh release in response to each AP, and 2) the muscle endplate—through extensive folding—provides a large surface area of nicotinic ACh receptors
Patients with myasthenia gravis respond immediately to…
Cholinesterase inhibitor
What do the cardiac glycosides do?
Antagonists of the Na+/K+ pump and are used in the treatment of congestive heart failure since they increase the strength of muscle contraction
Describe first and second pain
The first wave is mediated by large, myelinated axons (Aδ fibers), the second by smaller, non-myelinated axons which conduct more slowly (C fibers)
T/F: In contrast to ionotropic receptors, most G protein-coupled receptors give rise to smaller and slower EPSPs or IPSPs
True
Post-tetanic potentiation
Postsynaptic response is greater after a prior tetanus
Paired-pulse facilitation
Postsynaptic response is greater to a stimulus that comes rapidly after a prior stimulus
Paired-pulse facilitation and post-tetanic potentiation are both due to…What causes supprssed postsynaptic responses?
Ca2+ buildup; vesicle depletion
LTP involves what type of stimulation and activation of which receptors, allowing what through? What next?
High frequency stimulation; NMDA, Ca2+, phosphorylation (via CaMKII) and surface migration of AMPA receptors
How is LTD different?
Low-grade stimulation does not activate CaMKII, but rather Calcineurin, a phosphatase which removes AMPS receptors from the surface
