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Characteristics of tetanic force produced by the sternomastoid muscle of the rat.

Sobotka S, Mu L - J. Biomed. Biotechnol. (2010)

Bottom Line: It also has unique anatomical advantages that allow its wide use in head and neck tissue reconstruction and muscle reinnervation.However, little is known about its contractile properties.These data are important not only to better understand the contractile properties of the rat SM muscle, but also to provide normative values which are critical to reliably assess the extent of functional recovery following muscle reinnervation.

View Article: PubMed Central - PubMed

Affiliation: Department of Research, Upper Airway Research Laboratory, Hackensack University Medical Center, Hackensack, NJ 07601, USA.

ABSTRACT
The sternomastoid (SM) muscle plays an important role in supporting breathing. It also has unique anatomical advantages that allow its wide use in head and neck tissue reconstruction and muscle reinnervation. However, little is known about its contractile properties. The experiments were run on rats and designed to determine in vivo the relationship between muscle force (active muscle contraction to electrical stimulation) with passive tension (passive force changing muscle length) and two parameters (intensity and frequency) of electrical stimulation. The threshold current for initiating noticeable muscle contraction was 0.03 mA. Maximal muscle force (0.94 N) was produced by using moderate muscle length/tension (28 mm/0.08 N), 0.2 mA stimulation current, and 150 Hz stimulation frequency. These data are important not only to better understand the contractile properties of the rat SM muscle, but also to provide normative values which are critical to reliably assess the extent of functional recovery following muscle reinnervation.

No MeSH data available.


Related in: MedlinePlus

Muscle force as a function of stimulation current. This group average shows the density of force produced by the SM muscle and normalized by its cross-section area at different stimulation currents. Vertical bars represent the standard error of the mean. The passive tension was at a moderate level (0.08 N). The nerve was stimulated at 200 Hz.
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fig4: Muscle force as a function of stimulation current. This group average shows the density of force produced by the SM muscle and normalized by its cross-section area at different stimulation currents. Vertical bars represent the standard error of the mean. The passive tension was at a moderate level (0.08 N). The nerve was stimulated at 200 Hz.

Mentions: To examine the relationship between muscle force and stimulation current, we varied the current from 0 to 0.5 mA at 200 Hz trains of pulses when the muscle was stretched with moderate tension of 0.08 N, which produced optimal muscle length. Figure 3 shows the time course of muscle force responses to different stimulation currents in a representative rat. The difference between the maximal force produced by the SM muscle during nerve stimulation and the passive tension before stimulation was used to generate the current-force curve. The relationship between the density of force produced by the SM muscle (normalized by it's cross-section area) and stimulation current in the group average is shown in Figure 4. In most of our animals, 0.03 mA was the threshold current, which produced noticeable muscle contraction. Contraction force gradually increased with an increase of stimulation current until reaching the level of maximal muscle force at a stimulation current between 0.1 mA and 0.2 mA. In most of our animals, increasing stimulation current from 0.1 mA to 0.2 mA still produced an increase in muscle force (in average 11% increase—statistically significant increase P < .05, t = 2.3, two-tailed t-test for pairs, df = 11). Further increases of stimulation current did not increase muscle force.


Characteristics of tetanic force produced by the sternomastoid muscle of the rat.

Sobotka S, Mu L - J. Biomed. Biotechnol. (2010)

Muscle force as a function of stimulation current. This group average shows the density of force produced by the SM muscle and normalized by its cross-section area at different stimulation currents. Vertical bars represent the standard error of the mean. The passive tension was at a moderate level (0.08 N). The nerve was stimulated at 200 Hz.
© Copyright Policy - open-access
Related In: Results  -  Collection

Show All Figures
getmorefigures.php?uid=PMC2875700&req=5

fig4: Muscle force as a function of stimulation current. This group average shows the density of force produced by the SM muscle and normalized by its cross-section area at different stimulation currents. Vertical bars represent the standard error of the mean. The passive tension was at a moderate level (0.08 N). The nerve was stimulated at 200 Hz.
Mentions: To examine the relationship between muscle force and stimulation current, we varied the current from 0 to 0.5 mA at 200 Hz trains of pulses when the muscle was stretched with moderate tension of 0.08 N, which produced optimal muscle length. Figure 3 shows the time course of muscle force responses to different stimulation currents in a representative rat. The difference between the maximal force produced by the SM muscle during nerve stimulation and the passive tension before stimulation was used to generate the current-force curve. The relationship between the density of force produced by the SM muscle (normalized by it's cross-section area) and stimulation current in the group average is shown in Figure 4. In most of our animals, 0.03 mA was the threshold current, which produced noticeable muscle contraction. Contraction force gradually increased with an increase of stimulation current until reaching the level of maximal muscle force at a stimulation current between 0.1 mA and 0.2 mA. In most of our animals, increasing stimulation current from 0.1 mA to 0.2 mA still produced an increase in muscle force (in average 11% increase—statistically significant increase P < .05, t = 2.3, two-tailed t-test for pairs, df = 11). Further increases of stimulation current did not increase muscle force.

Bottom Line: It also has unique anatomical advantages that allow its wide use in head and neck tissue reconstruction and muscle reinnervation.However, little is known about its contractile properties.These data are important not only to better understand the contractile properties of the rat SM muscle, but also to provide normative values which are critical to reliably assess the extent of functional recovery following muscle reinnervation.

View Article: PubMed Central - PubMed

Affiliation: Department of Research, Upper Airway Research Laboratory, Hackensack University Medical Center, Hackensack, NJ 07601, USA.

ABSTRACT
The sternomastoid (SM) muscle plays an important role in supporting breathing. It also has unique anatomical advantages that allow its wide use in head and neck tissue reconstruction and muscle reinnervation. However, little is known about its contractile properties. The experiments were run on rats and designed to determine in vivo the relationship between muscle force (active muscle contraction to electrical stimulation) with passive tension (passive force changing muscle length) and two parameters (intensity and frequency) of electrical stimulation. The threshold current for initiating noticeable muscle contraction was 0.03 mA. Maximal muscle force (0.94 N) was produced by using moderate muscle length/tension (28 mm/0.08 N), 0.2 mA stimulation current, and 150 Hz stimulation frequency. These data are important not only to better understand the contractile properties of the rat SM muscle, but also to provide normative values which are critical to reliably assess the extent of functional recovery following muscle reinnervation.

No MeSH data available.


Related in: MedlinePlus