title: Tongue muscle plasticity following hypoglossal nerve stimulation in aged rats.
abstract: BACKGROUND
  Age-related decreases in tongue muscle mass and strength have been reported. It may be possible to prevent age-related tongue muscle changes using neuromuscular electrical stimulation (NMES). Our hypothesis was that alterations in muscle contractile properties and myosin heavy chain composition would be found after NMES.
  
  
  METHODS
  Fifty-four young, middle-aged, and old 344/Brown Norway rats were included in this study. Twenty-four rats underwent bilateral electrical stimulation of the hypoglossal nerves for 8 weeks and were compared with control or sham rats. Muscle contractile properties and myosin heavy chain (MHC) in the genioglossus (GG), styloglossus (SG), and hyoglossus (HG) muscles were examined.
  
  
  RESULTS
  Compared with unstimulated control rats, we found reduced muscle fatigue, increased contraction and half-decay times, and increased twitch and tetanic tension. Increased type I MHC was found, except for in GG in old and middle-aged rats.
  
  
  CONCLUSIONS
  Transitions in tongue muscle contractile properties and phenotype were found after NMES.
authors.affiliation: Department of Surgery, Otolaryngology-Head and Neck Surgery, 600 Highland Avenue, Room K4/711, University of Wisconsin, Madison, Wisconsin 53792, USA. connor@surgery.wisc.edu
authors.forename: Nadine P
authors.initials: NP
authors.lastname: Connor
authors.forename: John A
authors.initials: JA
authors.lastname: Russell
authors.forename: Michelle A
authors.initials: MA
authors.lastname: Jackson
authors.forename: Heidi
authors.initials: H
authors.lastname: Kletzien
authors.forename: Hao
authors.initials: H
authors.lastname: Wang
authors.forename: Allison J
authors.initials: AJ
authors.lastname: Schaser
authors.forename: Glen E
authors.initials: GE
authors.lastname: Leverson
authors.forename: David L
authors.initials: DL
authors.lastname: Zealear
mesh_terms: D000375:Aging / Q000502:physiology*; D000818:Animals; D004558:Electric Stimulation; D007002:Hypoglossal Nerve / Q000502:physiology*; D008297:Male; D009119:Muscle Contraction / Q000502:physiology; D018482:Muscle, Skeletal / Q000502:physiology*; D051381:Rats; D011914:Rats, Inbred BN; D014059:Tongue / Q000294:innervation* / Q000502:physiology