Effects of electrical stimulation on neuromuscular junction morphology in the aging rat tongue

Abstract

INTRODUCTION-Alterations in neuromuscular junction (NMJ) structure in cranial muscles may contribute to age-related deficits in critical sensorimotor actions such as swallowing. Neuromuscular electrical stimulation (NMES) is used in swallowing therapy, but it is unclear how NMJ structure is affected or if NMJ morphology is best measured in two or three dimensions.

The effect of age and tongue exercise on BDNF and TrkB in the hypoglossal nucleus of rats

“…Currently, our laboratory is using an animal model to study the underlying changes to the tongue musculature associated with progressive resistance exercise of the tongue [9, 10]. We have shown that tongue exercise induces changes in muscle fiber size and variability in the genioglossus muscle of aged rats that are associated with increased protrusive tongue forces.…”

“…We found that there was a trend toward an increase in muscle fiber size with tongue exercise and a significant increase in muscle fiber size variability with tongue exercise [9]. In addition, we have shown that neuromuscular stimulation results in a reduction in age-related changes to the morphology of the neuromuscular junction in aged rats [10]. In this study we used our previously described animal model to examine changes in neurotrophin levels in the hypoglossal nucleus of rats with both age and exercise.…”

Differential effects of targeted tongue exercise and treadmill running on aging tongue muscle structure and contractile properties

“…Age-related changes in GG muscle structure and physiology have been noted in humans and in animal models (11,15,28,45,50,56,67,68,71,75). Exercise may serve as an effective remediation because recent studies have identified increased GG muscle contraction amplitudes with exercise, as measured with electromyography (EMG) (73,83,88).…”

The role of synaptic laminins-α4 and -β2 in maturation and maintenance of the neuromuscular synapse

“…The density of VGCCs at each NMJ was measured through the division of the total number of puncta (based on each grouping stated) over the endplate volumes. Endplate volume was used as this parameter provide a more accurate determination of the VGCC puncta with respect to the three dimensional expansion of the endplate (Johnson & Connor, 2011).…”