Skip to main content
. Author manuscript; available in PMC: 2023 Feb 1.
Published in final edited form as: Stem Cell Rev Rep. 2021 Jul 1;18(2):768–780. doi: 10.1007/s12015-021-10201-2

Figure 2. Characterization of in vitro NMJs on a structural and functional level.

Figure 2.

The left side of the diagram lists key structural components of the NMJ that are often used to confirm proper differentiation of the source cells into motor neurons and skeletal myocytes, as well as the formation of an NMJ. The illustration on the right depicts aspects of determining the functionality of an in vitro NMJ. At a fully functioning NMJ, acetylcholine is released from the motor neuron and crosses the synaptic cleft to bind to acetylcholine receptors on the skeletal muscle membrane. This leads to a sodium ion influx into the muscle, calcium release from the sarcoplasmic reticulum, and contraction of the sarcomeres. Contractions may be stimulated through methods such as patch-clamp electrophysiology or modifying motor neurons to express channelrhodopsin (ChR2) and therefore create an action potential from light stimulation. There are also drugs and growth factors that can be added to either stimulate (e.g. glutamate or acetylcholine) or block (e.g. Botulinum toxin A, α-bungarotoxin, tubocurarine, or rocuronium) contractions.