title: Electrophysiologic assessment of sciatic nerve regeneration in the rat: surrounding limb muscles feature strongly in recordings from the gastrocnemius muscle.
abstract: Striking inconsistencies between the results of morphometric and electrophysiologic examinations of the regenerating nerve were observed in a previous study featuring the bridging of a 14 mm gap in the rat sciatic nerve. To shed light on this dichotomy, seven further rats were subjected to permanent sciatic nerve transection and assessed electrophysiologically, histologically and by retrograde axonal tracing at various postoperative intervals (1 h to 8 weeks). The results of the histological examinations and retrograde tracing revealed that in spite of the fact that compound muscle action potentials could be recorded in the gastrocnemius muscle, no reinnervation of the gastrocnemius muscle, either physiological or aberrant, had actually taken place. Furthermore, it was established that the electrical activity recorded in the gastrocnemius muscle after stimulation of the proximal or distal stump is generated by surrounding hind limb muscles unaffected by denervation. These are stimulated either directly, or indirectly due to spreading of the impulse. It is therefore strongly recommended that caution should be exercised when interpreting recordings from the gastrocnemius muscle after stimulation of a regenerating sciatic nerve in laboratory rodents.
authors.affiliation: Institute of Veterinary Pathology, Chair of General Pathology & Neuropathology, Ludwig-Maximilians University, Veterinärstr. 13, 80539 Munich, Germany.
authors.forename: Angie
authors.initials: A
authors.lastname: Rupp
authors.forename: Ulf
authors.initials: U
authors.lastname: Dornseifer
authors.forename: Andrea
authors.initials: A
authors.lastname: Fischer
authors.forename: Wolfgang
authors.initials: W
authors.lastname: Schmahl
authors.forename: Karsten
authors.initials: K
authors.lastname: Rodenacker
authors.forename: Uta
authors.initials: U
authors.lastname: Jütting
authors.forename: Peter
authors.initials: P
authors.lastname: Gais
authors.forename: Edgar
authors.initials: E
authors.lastname: Biemer
authors.forename: Nikolaos
authors.initials: N
authors.lastname: Papadopulos
authors.forename: Kaspar
authors.initials: K
authors.lastname: Matiasek
mesh_terms: D000200:Action Potentials / Q000502:physiology*; D000818:Animals; D004558:Electric Stimulation / Q000379:methods; D004566:Electrodes; D004576:Electromyography / Q000379:methods; D006614:Hindlimb / Q000294:innervation* / Q000503:physiopathology; D008297:Male; D018482:Muscle, Skeletal / Q000503:physiopathology*; D009416:Nerve Regeneration / Q000502:physiology*; D051381:Rats; D011917:Rats, Inbred Lew; D020426:Sciatic Neuropathy / Q000473:pathology / Q000503:physiopathology*; D013997:Time Factors