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Kunimichi Soma - One of the best experts on this subject based on the ideXlab platform.

  • Splenius muscle activities induced by temporomandibular joint stimulation in rats
    Brain research bulletin, 2006
    Co-Authors: Masaki Kobayashi, Tadachika Yabushita, Jorge L. Zeredo, Kazuo Toda, Kunimichi Soma
    Abstract:

    Abstract Recent studies show that temporomandibular joint disorders cause hyperalgesia and deficits in the postural control of cervical region. However, the effects of specific modalities of receptors in the temporomandibular joint area on these phenomena are still unclear. In this study, we investigated the neck muscle activities while natural mechanical stimulation was applied to the temporomandibular joint. Single motor unit activities were recorded bilaterally from the Splenius Muscles in 22 Wistar rats. Mechanical stimulation applied to the left temporomandibular joint elicited tonic discharges in the left or right Splenius muscle. The mean threshold values for mechanical stimulation were 48.1 (±16.2 S.E.M.) and 54.1 mN (±16.3 S.E.M.) for left and right sides, respectively. It is suggested that the temporomandibular joint mechanoreceptors not only affect the motor unit activities of neck Muscles, but also are concerned in the regulation of postural control of the head.

  • Nature of Neck Motor Unit Activities Evoked by Different Trigeminal Inputs in Rats
    Journal of dental research, 2003
    Co-Authors: Jorge L. Zeredo, Kazuo Toda, Kunimichi Soma
    Abstract:

    Recent reports have suggested functional interactions between the masticatory and head motor systems. However, the neurophysiological mechanisms behind these phenomena have not been thoroughly investigated. In this study, the motor unit activity was recorded bilaterally from the dorsal neck Splenius Muscles (SPL) while the cell bodies of trigeminal afferent fibers were stimulated at either the trigeminal mesencephalic nucleus (Me5) or the Gasserian ganglion (5Gn) in 13 barbiturate-anesthetized Wistar rats. After Me5 electrical stimulation, SPL motor unit responses were recorded ipsilaterally (n = 24), with an onset latency distribution between 1.3 and 1.8 ms. After 5Gn stimulation, SPL responses were recorded bilaterally from 18 single units, with latencies ranging from 2.2 to 2.4 ms. Our results suggest that there are at least two distinct pathways from the trigeminal afferents to the neck Muscles, with significant functional differences.

  • Neck Motor Unit Activities Induced by Inputs from Periodontal Mechanoreceptors in Rats
    Journal of dental research, 2002
    Co-Authors: Jorge L. Zeredo, Kazuo Toda, Kunimichi Soma
    Abstract:

    Clinical evidence suggests that head movements may be coupled with oro-facial functions, which are predominantly controlled by somatosensory inputs from the oro-facial area. However, the effects of specific modalities of sensory inputs on the neck Muscles’ motor activity are still unclear. In the present study, natural pressure stimulation was applied to the rat's upper first molars, while motor unit electromyographic activity was recorded from the dorsal neck Splenius muscle. During the hold phase of pressure stimulation, clear tonic discharges were elicited in the Splenius Muscles on both sides. Mean threshold values were 622.3 mN (± 19.6 SEM, n = 39) and 496.8 mN (± 26.4 SEM, n = 43) for ipsi- and contralateral sides, respectively (p < 0.001, Mann-Whitney U test). Analysis of our data suggests that periodontal inputs may play an important role in controlling the motor activity of neck Muscles, in addition to its well-known coordination of the masticatory function.

Hakan Johansson - One of the best experts on this subject based on the ideXlab platform.

  • Increased intra-articular concentration of bradykinin in the temporomandibular joint changes the sensitivity of muscle spindles in dorsal neck Muscles in the cat
    Neuroscience research, 2002
    Co-Authors: Fredrik Hellstrom, Johan Thunberg, Per Sjolander, Mikael Bergenheim, Mats Djupsjöbacka, Hakan Johansson
    Abstract:

    Abstract The aim of the present study was to investigate to what extent activation of bradykinin-sensitive nerve endings of the temporomandibular joint (TMJ) might induce changes in the muscle spindles output from neck Muscles through reflex effects on cervical fusimotor neurones. To this end, 26 muscle spindle afferents (MSAs) emanating from the trapezius and Splenius Muscles of the anaesthetised cat (α-chloralose, initial dosage 60 mg/kg) were recorded during injection of Bradykinin (BK) (12.5–50 μg/ml) in the ipsilateral TMJ. Fifteen (58%) MSAs exhibited statistically significant fusimotor effects to injection of BK into the TMJ. Of the 15, ten MSAs showed a response related to activation of static fusimotor neurones, three MSAs showed a response related to an activation of both static and dynamic fusimotor neurones and two MSAs showed a inhibition of both static and dynamic fusimotor neurones. The control experiments suggests that the effects observed were due to activation of BK sensitive nerve endings in the TMJ. It seems possible that the reflex connections between TMJ nociceptors and the fusimotor-muscle spindle system of dorsal neck Muscles might be involved in the pathophysiological mechanisms responsible for the sensory-motor disturbances in the neck region often found on patients with temporomandibular disorders.

  • influences on the fusimotor muscle spindle system from chemosensitive nerve endings in cervical facet joints in the cat possible implications for whiplash induced disorders
    Pain, 2001
    Co-Authors: Johan Thunberg, Per Sjolander, Mikael Bergenheim, Britt Inger Wenngren, Fredrik Hellstrom, Hakan Johansson
    Abstract:

    Abstract The aim of the present study was to establish if there exists reflex connections from ligamentous structures in cervical facet joints and the fusimotor system of dorsal neck Muscles. In seven cats, anaesthetized with α-chloralose, bradykinin (BK) of concentrations between 12 and 50 μg was injected into the facet joint between C1 and C2. Recordings were made from single muscle spindle afferents (MSA) originating in contralateral trapezius and Splenius Muscles (TrSp). Fusimotor induced changes in the sensitivity of the muscle spindle afferents were assessed by recording the responses to sinusoidal stretches of the TrSp Muscles. The mean rate of discharge and the depth of modulation of a fitted sine were taken as quantitative estimates of the response. A total of 25 MSAs were recorded, and 21 of these showed clear-cut alterations in their responses to the sinusoidal stretches following Bk. injections into contralateral facet joint. The majority of the responding afferents (13/21) showed changes in their responses indicating an increased activity of static fusimotoneurones, although responses of dynamic and mixed static and dynamic nature were also seen. Local anaesthetics applied to the intraarticular receptors abolished the effects. Injection (i.v.) of a general anaesthetic (pentobarbital) abolished the effects. The results show that there exist reflex connections between receptors in cervical facet joints and fusimotoneurones of dorsal neck Muscles, and this might be of importance in the pathophysiology behind whiplash associated disorders (WAD).

  • Elevated Intramuscular Concentration of Bradykinin in Jaw Muscle Increases the Fusimotor Drive to Neck Muscles in the Cat
    Journal of dental research, 2000
    Co-Authors: Fredrik Hellstrom, Johan Thunberg, Per Sjolander, Mikael Bergenheim, J Pedersen, Hakan Johansson
    Abstract:

    Patients suffering from temporomandibular dysfunction exhibit clinical findings such as fatigue, painful Muscles, and Muscles that are tender to palpation, not only in the temporomandibular area, but also in the neck/shoulder region. The mechanisms behind this are not known, although previous studies of similar spreading phenomena have revealed a possible involvement of the fusimotor system. In the present study, we evaluated the activity of this system by recording the activity of muscle spindle afferents from dorsal neck Muscles after intramuscular injections of 6 microg to 25 microg bradykinin in the ipsilateral masseter muscle. A total of 23 muscle spindle afferents from the trapezius and Splenius Muscles was recorded at the C3-C4 level in 7 adult cats anesthetized with alpha-chloralose. Of these 23 afferents, 17 (74%) showed significantly different responses to bradykinin injections compared with control injections (dissolving agent, Tyrode), and the majority of the effects were compatible with an increased static fusimotor drive to the muscle spindle system. Thus, the results demonstrate potent reflex connections from groups III and IV masseter muscle afferents to fusimotor neurones on the C3-C4 level. It is concluded that the fusimotor system might play a significant role in the mechanisms behind the spread of muscle pain and tension from the temporomandibular region to the neck.

Masaki Kobayashi - One of the best experts on this subject based on the ideXlab platform.

Johan Thunberg - One of the best experts on this subject based on the ideXlab platform.

  • Responses of muscle spindles in feline dorsal neck Muscles to electrical stimulation of the cervical sympathetic nerve
    Experimental Brain Research, 2005
    Co-Authors: F. Hellström, Johan Thunberg, S. Roatta, M. Passatore, M. Djupsjöbacka
    Abstract:

    Previous studies performed in jaw Muscles of rabbits and rats have demonstrated that sympathetic outflow may affect the activity of muscle spindle afferents (MSAs). The resulting impairment of MSA information has been suggested to be involved in the genesis and spread of chronic muscle pain. The present study was designed to investigate sympathetic influences on muscle spindles in feline trapezius and Splenius Muscles (TrSp), as these Muscles are commonly affected by chronic pain in humans. Experiments were carried out in cats anesthetized with alpha-chloralose. The effect of electrical stimulation (10 Hz for 90 s or 3 Hz for 5 min) of the peripheral stump of the cervical sympathetic nerve (CSN) was investigated on the discharge of TrSp MSAs (units classified as Ia-like and II-like) and on their responses to sinusoidal stretching of these Muscles. In some of the experiments, the local microcirculation of the Muscles was monitored by laser Doppler flowmetry. In total, 46 MSAs were recorded. Stimulation of the CSN at 10 Hz powerfully depressed the mean discharge rate of the majority of the tested MSAs (73%) and also affected the sensitivity of MSAs to sinusoidal changes of muscle length, which were evaluated in terms of amplitude and phase of the sinusoidal fitting of unitary activity. The amplitude was significantly reduced in Ia-like units and variably affected in II-like units, while in general the phase was affected little and not changed significantly in either group. The discharge of a smaller percentage of tested units was also modulated by 3-Hz CSN stimulation. Blockade of the neuromuscular junctions by pancuronium did not induce any changes in MSA responses to CSN stimulation, showing that these responses were not secondary to changes in extrafusal or fusimotor activity. Further data showed that the sympathetically induced modulation of MSA discharge was not secondary to the concomitant reduction of muscle blood flow induced by the stimulation. Hence, changes in sympathetic outflow can modulate the afferent signals from muscle spindles through an action exerted directly on the spindles, independent of changes in blood flow. It is suggested that such an action may be one of the mechanisms mediating the onset of chronic muscle pain in these Muscles in humans.

  • Increased intra-articular concentration of bradykinin in the temporomandibular joint changes the sensitivity of muscle spindles in dorsal neck Muscles in the cat
    Neuroscience research, 2002
    Co-Authors: Fredrik Hellstrom, Johan Thunberg, Per Sjolander, Mikael Bergenheim, Mats Djupsjöbacka, Hakan Johansson
    Abstract:

    Abstract The aim of the present study was to investigate to what extent activation of bradykinin-sensitive nerve endings of the temporomandibular joint (TMJ) might induce changes in the muscle spindles output from neck Muscles through reflex effects on cervical fusimotor neurones. To this end, 26 muscle spindle afferents (MSAs) emanating from the trapezius and Splenius Muscles of the anaesthetised cat (α-chloralose, initial dosage 60 mg/kg) were recorded during injection of Bradykinin (BK) (12.5–50 μg/ml) in the ipsilateral TMJ. Fifteen (58%) MSAs exhibited statistically significant fusimotor effects to injection of BK into the TMJ. Of the 15, ten MSAs showed a response related to activation of static fusimotor neurones, three MSAs showed a response related to an activation of both static and dynamic fusimotor neurones and two MSAs showed a inhibition of both static and dynamic fusimotor neurones. The control experiments suggests that the effects observed were due to activation of BK sensitive nerve endings in the TMJ. It seems possible that the reflex connections between TMJ nociceptors and the fusimotor-muscle spindle system of dorsal neck Muscles might be involved in the pathophysiological mechanisms responsible for the sensory-motor disturbances in the neck region often found on patients with temporomandibular disorders.

  • influences on the fusimotor muscle spindle system from chemosensitive nerve endings in cervical facet joints in the cat possible implications for whiplash induced disorders
    Pain, 2001
    Co-Authors: Johan Thunberg, Per Sjolander, Mikael Bergenheim, Britt Inger Wenngren, Fredrik Hellstrom, Hakan Johansson
    Abstract:

    Abstract The aim of the present study was to establish if there exists reflex connections from ligamentous structures in cervical facet joints and the fusimotor system of dorsal neck Muscles. In seven cats, anaesthetized with α-chloralose, bradykinin (BK) of concentrations between 12 and 50 μg was injected into the facet joint between C1 and C2. Recordings were made from single muscle spindle afferents (MSA) originating in contralateral trapezius and Splenius Muscles (TrSp). Fusimotor induced changes in the sensitivity of the muscle spindle afferents were assessed by recording the responses to sinusoidal stretches of the TrSp Muscles. The mean rate of discharge and the depth of modulation of a fitted sine were taken as quantitative estimates of the response. A total of 25 MSAs were recorded, and 21 of these showed clear-cut alterations in their responses to the sinusoidal stretches following Bk. injections into contralateral facet joint. The majority of the responding afferents (13/21) showed changes in their responses indicating an increased activity of static fusimotoneurones, although responses of dynamic and mixed static and dynamic nature were also seen. Local anaesthetics applied to the intraarticular receptors abolished the effects. Injection (i.v.) of a general anaesthetic (pentobarbital) abolished the effects. The results show that there exist reflex connections between receptors in cervical facet joints and fusimotoneurones of dorsal neck Muscles, and this might be of importance in the pathophysiology behind whiplash associated disorders (WAD).

  • Elevated Intramuscular Concentration of Bradykinin in Jaw Muscle Increases the Fusimotor Drive to Neck Muscles in the Cat
    Journal of dental research, 2000
    Co-Authors: Fredrik Hellstrom, Johan Thunberg, Per Sjolander, Mikael Bergenheim, J Pedersen, Hakan Johansson
    Abstract:

    Patients suffering from temporomandibular dysfunction exhibit clinical findings such as fatigue, painful Muscles, and Muscles that are tender to palpation, not only in the temporomandibular area, but also in the neck/shoulder region. The mechanisms behind this are not known, although previous studies of similar spreading phenomena have revealed a possible involvement of the fusimotor system. In the present study, we evaluated the activity of this system by recording the activity of muscle spindle afferents from dorsal neck Muscles after intramuscular injections of 6 microg to 25 microg bradykinin in the ipsilateral masseter muscle. A total of 23 muscle spindle afferents from the trapezius and Splenius Muscles was recorded at the C3-C4 level in 7 adult cats anesthetized with alpha-chloralose. Of these 23 afferents, 17 (74%) showed significantly different responses to bradykinin injections compared with control injections (dissolving agent, Tyrode), and the majority of the effects were compatible with an increased static fusimotor drive to the muscle spindle system. Thus, the results demonstrate potent reflex connections from groups III and IV masseter muscle afferents to fusimotor neurones on the C3-C4 level. It is concluded that the fusimotor system might play a significant role in the mechanisms behind the spread of muscle pain and tension from the temporomandibular region to the neck.

Marzieh Mohamadi - One of the best experts on this subject based on the ideXlab platform.

  • Can muscle relaxation affect balance in patients with tension-type headache? A pre-post study
    2018
    Co-Authors: Zahra Rojhani-shirazi, Ali Barzegar, Elham Nouraddini, Negar Ajdari, Marzieh Mohamadi
    Abstract:

    Background: Proprioceptive inputs from the cervical region play an important role in balance. In patients with tension-type headache (TTH), proprioception is altered. The effect of treatment for TTH on balance is unclear. The aim of this study was to evaluate the effectiveness of post-isometric relaxation (PIR) in the neck Muscles on pain, disability and balance in patients with TTH. Methods: 30 patients with chronic TTH who had a trigger point and tenderness in the upper trapezius, sternocleidomastoid (SCM), suboccipitalor Splenius Muscles were enrolled in the study. The patients underwent PIR based on Liebenson’s method. Before and after treatment, balancewas evaluated with the Y balance test, time up and go test, functional reach test and single leg stance test. As clinical symptoms of TTH we considered the intensity and frequency of headaches,which were recorded along with neck disability index (NDI)assecondary outcomes. Paired t-tests were used to analyze the data. Results: The results of the Y balance test, time up and go test, functional reach test and single leg stance test changed significantly after treatment (P< 0.001). Significant differences were also found forall secondary variables (P < 0.001). Conclusions: The results of this study showed that the PIR technique for muscle relaxation in the upper trapezius, SCM, suboccipitalor Splenius Muscles may improve balance along with clinical symptoms such as pain and disabilityin patients with TTH.

  • Can Muscle Relaxation Affect Balance in Patients with Tension-Type Headache? A Pre-Post Study
    Shiraz University of Medical Sciences, 2017
    Co-Authors: Zahra Rojhani-shirazi, Ali Barzegar, Marzieh Mohamadi
    Abstract:

    Background: Proprioceptive inputs from the cervical region play an important role in balance. In patients with tension-type headache (TTH), proprioception is altered. The effect of treatment for TTH on balance is unclear. The aim of this study was to evaluate the effectiveness of post-isometric relaxation (PIR) in the neck Muscles on pain, disability and balance in patients with TTH. Methods: 30 patients with chronic TTH who had a trigger point and tenderness in the upper trapezius, sternocleidomastoid (SCM), suboccipital or Splenius Muscles were enrolled in the study. The patients underwent PIR based on Liebenson’s method. Before and after treatment, balance was evaluated with the Y balance test, time up and go test, functional reach test and single leg stance test. As clinical symptoms of TTH we considered the intensity and frequency of headaches,which were recorded along with neck disability index (NDI) as secondary outcomes. Paired t-tests were used to analyze the data. Results: The results of the Y balance test, time up and go test, functional reach test and single leg stance test changed significantly after treatment (P