electrophysiological assessment of neuromuscular transmission

Acetyl co A +Choline

Cholineacetylase

Ach synthesis

Main store

Mobilization pool

Immediately available pool

Depolarisation->EPP->MAP

ACh->Acetic acid+choline

Synapticcleft

Vesicles in the synaptic terminal fuse with the neuronal membrane and dump their contents into the synaptic cleft.

The binding of ACh to the receptors increases the membrane permeability to sodium ions. Sodium ions then rush into the cell.

An action potential spreads across the surface of the sarcolemma. While this occurs, AChE removes the ACh.

Appearance of an action potential in the sarcolemma

ACh binding at the motor and plateRelease of acetylcholine

Arrival of an action potential at the synaptic terminal

Sarcolemma ofmotor end plate

Arriving action potential

Vesicles

ACh

AChE molecules

AChreceptorsite

Action potential

Synaptic terminal

Axon

Sarcolemma

Musclefiber

Actionpotential

Na+

Na+

Na+

Synapticcleft

Vesicles in the synaptic terminal fuse with the neuronal membrane and dump their contents into the synaptic cleft.

The binding of ACh to the receptors increases the membrane permeability to sodium ions. Sodium ions then rush into the cell.

An action potential spreads across the surface of the sarcolemma. While this occurs, AChE removes the ACh.

Appearance of an action potential in the sarcolemma

ACh binding at the motor and plateRelease of acetylcholine

Arrival of an action potential at the synaptic terminal

Sarcolemma ofmotor end plate

Arriving action potential

Vesicles

ACh

AChE molecules

AChreceptorsite

Action potential

Synaptic terminal

Axon

Sarcolemma

Musclefiber

Actionpotential

Na+

Na+

Na+

Synapticcleft

Vesicles in the synaptic terminal fuse with the neuronal membrane and dump their contents into the synaptic cleft.

The binding of ACh to the receptors increases the membrane permeability to sodium ions. Sodium ions then rush into the cell.

An action potential spreads across the surface of the sarcolemma. While this occurs, AChE removes the ACh.

Appearance of an action potential in the sarcolemma

ACh binding at the motor and plateRelease of acetylcholine

Arrival of an action potential at the synaptic terminal

Sarcolemma ofmotor end plate

Arriving action potential

Vesicles

ACh

AChE molecules

AChreceptorsite

Action potential

Synaptic terminal

Axon

Sarcolemma

Musclefiber

Actionpotential

Na+

Na+

Na+

Myasthenia GravisRepetitive Nerve Stimulation

baseline

Post exercise

2 minutes

3 minutes

Repeat exercise

Single Fiber EMGMyasthenia Gravis

Synapticcleft

Vesicles in the synaptic terminal fuse with the neuronal membrane and dump their contents into the synaptic cleft.

The binding of ACh to the receptors increases the membrane permeability to sodium ions. Sodium ions then rush into the cell.

An action potential spreads across the surface of the sarcolemma. While this occurs, AChE removes the ACh.

Appearance of an action potential in the sarcolemma

ACh binding at the motor and plateRelease of acetylcholine

Arrival of an action potential at the synaptic terminal

Sarcolemma ofmotor end plate

Arriving action potential

Vesicles

ACh

AChE molecules

AChreceptorsite

Action potential

Synaptic terminal

Axon

Sarcolemma

Musclefiber

Actionpotential

Na+

Na+

Na+

Synapticcleft

Vesicles in the synaptic terminal fuse with the neuronal membrane and dump their contents into the synaptic cleft.

The binding of ACh to the receptors increases the membrane permeability to sodium ions. Sodium ions then rush into the cell.

An action potential spreads across the surface of the sarcolemma. While this occurs, AChE removes the ACh.

Appearance of an action potential in the sarcolemma

ACh binding at the motor and plateRelease of acetylcholine

Arrival of an action potential at the synaptic terminal

Sarcolemma ofmotor end plate

Arriving action potential

Vesicles

ACh

AChE molecules

AChreceptorsite

Action potential

Synaptic terminal

Axon

Sarcolemma

Musclefiber

Actionpotential

Na+

Na+

Na+

Ca2+ channel structure

2

1

Synapticcleft

Vesicles in the synaptic terminal fuse with the neuronal membrane and dump their contents into the synaptic cleft.

The binding of ACh to the receptors increases the membrane permeability to sodium ions. Sodium ions then rush into the cell.

An action potential spreads across the surface of the sarcolemma. While this occurs, AChE removes the ACh.

Appearance of an action potential in the sarcolemma

ACh binding at the motor and plateRelease of acetylcholine

Arrival of an action potential at the synaptic terminal

Sarcolemma ofmotor end plate

Arriving action potential

Vesicles

ACh

AChE molecules

AChreceptorsite

Action potential

Synaptic terminal

Axon

Sarcolemma

Musclefiber

Actionpotential

Na+

Na+

Na+

Synapticcleft

Vesicles in the synaptic terminal fuse with the neuronal membrane and dump their contents into the synaptic cleft.

The binding of ACh to the receptors increases the membrane permeability to sodium ions. Sodium ions then rush into the cell.

An action potential spreads across the surface of the sarcolemma. While this occurs, AChE removes the ACh.

Appearance of an action potential in the sarcolemma

ACh binding at the motor and plateRelease of acetylcholine

Arrival of an action potential at the synaptic terminal

Sarcolemma ofmotor end plate

Arriving action potential

Vesicles

ACh

AChE molecules

AChreceptorsite

Action potential

Synaptic terminal

Axon

Sarcolemma

Musclefiber

Actionpotential

Na+

Na+

Na+

SCS

Choline acetyl transferase deficiency

20 Hz

Summary