Author/Editor		Trontelj, Jože V; Mihelin, Marjan; Khuraibet, Adnan
Title		Safety margin at single neuromuscular junctions
Type		članek
Source		Muscle Nerve
Vol. and No.		, št. Suppl 11
Publication year		2002
Volume		str. S21-7
Language		eng
Abstract		Jitter measurement with axonal microstimulation was used to study synaptic function at 115 neuromuscular junctions (NMJs) of normal subjects at various stimulation rates. Jitter was lowest at 0.5 Hz; it increased slightly at 1, 2, and 5 Hz and remained at that level at 10 Hz (a light work load) and 20 Hz (a heavy work load); and it increased further at 50 Hz (an extreme load). This pattern was seen for the majority of the NMJs, suggesting a high safety factor of neuromuscular transmission maintained rather uniformly over a wide range of discharge rates. A proportion of the normal NMJs had relatively large jitter; these tended to show prominent facilitation as the rate was raised from 5 or 10 to 20 Hz. Similar but more dramatic facilitation improving the safety factor was seen at most NMJs in myasthenia, which was studied for comparison. Such facilitation was not found at normal NMJs with low jitter.
Descriptors		NEUROMUSCULAR JUNCTION NEURAL CONDUCTION ACTION POTENTIALS ELECTROMYOGRAPHY MUSCLE, SKELETAL ADULT MUSCLE FIBERS MOTOR ENDPLATE