title: Degeneration and recovery of the neuromuscular junction after application of extracorporeal shock wave therapy.
abstract: It is known that free nerve endings are degenerated after application of shock waves. We therefore hypothesized that the application of shock waves to muscle induces dysfunction of neuromuscular transmission at neuromuscular junctions. We investigated changes in neuromuscular transmission in response to shock wave application. Sprague-Dawley rats were used in this study. Two thousand shock waves at an energy flux density of 0.18 mJ/mm(2) were applied to their right calf muscles. Neuromuscular junctions of gastrocnemius muscles were evaluated using rhodamine-α-bungarotoxin on the day of treatment (n  =  5). Amplitude and latency of compound muscle action potentials were measured on the day of treatment and 1, 2, 4, 6, and 8 weeks after treatment (n  =  10, each group). Degenerated acetylcholine receptors existed in all treated muscles. Although the action potential amplitude on the treated side was significantly less than on the control side from the day of treatment (25.1 ± 7.8 vs. 34.5 ± 9.1, p  =  0.012) to 6 weeks (27.9 ± 7.2 vs. 34.5 ± 7.2, p  =  0.037), there was no significant difference at 8 weeks. There was no significant difference in transmission latency between the groups. The application of shock waves to muscle induced a transient dysfunction of nerve conduction at neuromuscular junctions.
authors.affiliation: Department of Orthopaedic Surgery, Chiba University Graduated School of Medicine, Chiba, Japan. pseudolefty811@yahoo.co.jp
authors.forename: Tomonori
authors.initials: T
authors.lastname: Kenmoku
authors.forename: Nobuyasu
authors.initials: N
authors.lastname: Ochiai
authors.forename: Seiji
authors.initials: S
authors.lastname: Ohtori
authors.forename: Takashi
authors.initials: T
authors.lastname: Saisu
authors.forename: Takahisa
authors.initials: T
authors.lastname: Sasho
authors.forename: Koichi
authors.initials: K
authors.lastname: Nakagawa
authors.forename: Nahoko
authors.initials: N
authors.lastname: Iwakura
authors.forename: Masayuki
authors.initials: M
authors.lastname: Miyagi
authors.forename: Tetsuhiro
authors.initials: T
authors.lastname: Ishikawa
authors.forename: Hodumi
authors.initials: H
authors.lastname: Tatsuoka
authors.forename: Gen
authors.initials: G
authors.lastname: Inoue
authors.forename: Junichi
authors.initials: J
authors.lastname: Nakamura
authors.forename: Shunji
authors.initials: S
authors.lastname: Kishida
authors.forename: Atsushi
authors.initials: A
authors.lastname: Saito
authors.forename: Kazuhisa
authors.initials: K
authors.lastname: Takahashi
mesh_terms: D000818:Animals; D004421:Dystonia / Q000628:therapy*; D019220:High-Energy Shock Waves / Q000009:adverse effects*; D008297:Male; D009128:Muscle Spasticity / Q000628:therapy*; D009469:Neuromuscular Junction / Q000528:radiation effects*; D051381:Rats; D017207:Rats, Sprague-Dawley; D011950:Receptors, Cholinergic / Q000528:radiation effects; D059708:Ultrasonic Surgical Procedures
chemical_list: D011950:Receptors, Cholinergic