Lecture 10 - Electrophysiology and Synaptic Transmission

Question 1

Na+/K+ ATPase is comprised of 3 subunits.

The Alpha subunit is involved with the _______ of _____ and Binding of _____.

The Beta subunit is involved with both insertion of the pump into the _____ and _____ binding.

The Gamma subunit controls the _______ of Na+, K+, and ATP binding.

Answer 1

Alpha –> Hydrolysis of ATP and Cation binding

Beta –> Membrane Insertion and Ion binding

Gamma –> Controls Binding affinities

Question 2

SNARE proteins facilitate Vesicle fusion with the Presynaptic membrane for NT release into the Synapse. Which of the following SNARE proteins are on the Vesicle and which are on the Presynaptic membrane?

Synaptobrevin

Synaptotagmin

SNAP-25

Syntaxin

Answer 2

Synaptobrevin and Synaptotagmin –> Vesicle

SNAP-25 and Syntaxin –> Presynaptic membrane

Question 3

Ca++ binds ______ (which SNARE protein?) and causes fusion of the vesicle with the membrane.

Answer 3

Synaptotagmin

Question 4

Vesicles can be recycled by first being coated with ______ while they are fused with the Presynaptic membrane –> then pinched off intracellularly by _____ –> then Uncoated in a process requiring ATPase activity –> Then bound to the intracellular Cytoskeleton via _______.

Answer 4

Clathrin

Dynamin

Synapsin

Question 5

Botulinum toxin is selectively taken up by ______ neurons where it cleaves SNARE proteins ______, _____, and ______ –> inhibits the release of ACH.

Answer 5

Motor Neurons

Synaptobrevin, SNAP-25, and Syntaxin

Question 6

Tetanus toxin is selectively taken up by ____ ______ where it cleaves ________ –> inhibits the release of _____.

Answer 6

Spinal Interneurons

Synaptobrevin

GABA

Question 7

Symmetrical synapses, where the Presynaptic membrane is the same thickness as the Postsynaptic membrane, are typically _______ pathways. Asymmetrical synapses, where the Postsynaptic membrane is Thicker than the Presynaptic membrane, are typically ______ pathways.

Answer 7

Inhibitory

Excitatory

Question 8

Metabotropic Ion receptors are typically ______ (faster or slower?) to act but have a _____ (longer or shorter?) duration of action than Voltage or Ligand-gated Ion channels.

Answer 8

Slower

Longer

Question 9

Central Synaptic transmission differs from Peripheral Synaptic transmission in that Central Synaptic Potentials are ______ (not all-or-nothing). Also, Central Synaptic Potentials do not have a ______ period.

Answer 9

Graded

Refractory

Question 10

In Myasthenia Gravis, Autoantibodies inhibit the _______ receptors on postsynaptic membrane of motor end plate. Concordantly, it is treated with __________ inhibitors –> increases [ACH] at the NMJ.

Repeated RAPID stimulation results in Decremental (decreasing) response.

Answer 10

ACH

Acetylcholinesterase inhibitors

Question 11

In Lambert-Eaton syndrome, ACH release is inhibited via Autoantibodies that bind and inhibit ______-______ _____ channels, so it affects both Motor neurons AND _______ Autonomic neurons.

Repeated RAPID stimulation results in _______ response (opposite of Myasthenia Gravis).

Answer 11

Voltage-gated Ca++

Preganglionic Autonomic Neurons

Incremental