Jaw muscle (EMG) activity and amplitude scaling of jaw movements during eating in pigeon (Columba livia)

1994 ◽  
Vol 174 (4) ◽  
Author(s):  
R. Bout ◽  
H.P. Zeigler
1999 ◽  
Vol 43 (5) ◽  
pp. 918-922
Author(s):  
Tadashi Yoshimatsu ◽  
Tetsuro Torisu ◽  
Yoshihisa Yamabe ◽  
Kazuko Noguchi ◽  
Nobuyuki Hashimoto ◽  
...  

2001 ◽  
Vol 85 (6) ◽  
pp. 2446-2454 ◽  
Author(s):  
Brian E. Cairns ◽  
Barry J. Sessle ◽  
James W. Hu

Injection of glutamate into the rat temporomandibular joint (TMJ) capsule can reflexly induce a prolonged increase in the electromyographic (EMG) activity of the jaw muscles, however, the characteristics of TMJ afferents activated by glutamate have not been investigated. In the present study, we examined the effect of glutamate injection into the TMJ capsule on jaw muscle EMG activity and the extracellularly recorded activity of single trigeminal afferents that had receptive fields in the TMJ tissue and antidromically identified projections to the brain stem subnucleus caudalis (Vc) in rats of both sexes. Glutamate (0.05–1.0 M, 10 μl) injection into the TMJ capsule evoked EMG activity in a dose-related manner; however, at concentrations of 0.5 and 1.0 M, glutamate-evoked digastric muscle responses were greater in female than in male rats. In experiments where jaw muscle EMG and afferent activity were recorded simultaneously, glutamate (0.5 M, 10 μl) injection into the TMJ capsule evoked activity in the jaw muscles as well as in 27 (26 Aδ and 1 C-fiber afferent) of 34 trigeminal afferents that could be activated by blunt mechanical stimulation of the TMJ tissue. In these experiments, glutamate-evoked jaw muscle activity was significantly increased for 6 min after the glutamate injection, whereas afferent activity was significantly increased only during the first minute after the glutamate injection. The glutamate-evoked afferent activity was inversely related to conduction velocity and, in afferents with conduction velocities <10 m/s, was significantly greater in female ( n = 6) than in male ( n = 10) rats. These results suggest that glutamate excites putative nociceptive afferents within the TMJ to a greater degree in female than in male rats. This sex-related difference in afferent discharge may, in part, underlie sex-related differences in glutamate-evoked jaw muscle EMG activity.


1999 ◽  
Vol 81 (4) ◽  
pp. 1966-1969 ◽  
Author(s):  
Brian E. Cairns ◽  
Barry J. Sessle ◽  
James W. Hu

Activation of peripheral GABAA receptors inhibits temporomandibular joint–evoked jaw muscle activity. We have previously shown that injection of mustard oil or glutamate into rat temporomandibular joint (TMJ) tissues, an experimental model of acute TMJ injury, can reflexly induce a prolonged increase in the activity of both digastric (jaw-opener) and masseter (jaw-closer) muscles. In this study, GABA was applied to the TMJ region by itself or in combination with glutamate, and the magnitude of evoked jaw muscle electromyographic (EMG) activity was measured. Application of GABA alone to the TMJ region did not evoke significant jaw muscle EMG activity when compared with normal saline controls. In contrast, co-application of GABA and glutamate into the TMJ region decreased the magnitude of glutamate-evoked EMG activity. This GABA-mediated inhibition of glutamate-evoked EMG activity followed an inverse dose-response relationship with an estimated median inhibitory dose (ID50) of 0.17 ± 0.05 (SE) μmol and 0.031 ± 0.006 μmol for the digastric and masseter muscles, respectively. Co-administration of the GABAA receptor antagonist bicuculline (0.05 μmol) but not the GABABreceptor antagonist phaclofen (0.05 or 0.15 μmol) reversed the suppressive actions of GABA, indicating that this action of GABA may be mediated by peripheral GABAA receptors located within the TMJ region. Our results suggest that activation of peripheral GABAA receptors located within the TMJ region could act to decrease the transmission of nociceptive information.


1994 ◽  
Vol 72 (3) ◽  
pp. 1430-1433 ◽  
Author(s):  
X. M. Yu ◽  
B. J. Sessle ◽  
H. Vernon ◽  
J. W. Hu

1. Our recent studies in rats have demonstrated that the small-fiber excitant and inflammatory irritant mustard oil injected into the temporomandibular joint (TMJ) region can evoke a sustained and reversible increase of electromyographic (EMG) activity in jaw muscles and an acute inflammatory response. The aim of the present study was to test if opioid mechanisms are involved in modulating the EMG increase evoked by mustard oil. 2. Mustard oil injected into the rat TMJ region evoked significant increases of jaw muscle EMG activity; the vehicle mineral oil had no such effect. The increased EMG activity lasted up to 20 min, and by 30 min after the mustard oil injection had returned to control (preinjection) levels, at which time administration of the opiate antagonist naloxone (1.3 mg/kg i.v.) induced a significant recurrence of the increase in EMG activity. This "rekindling" of EMG activity appeared at 5 to 10 min after the naloxone administration and lasted for 10 to 20 min. In contrast, naloxone administration in the animals receiving mineral oil injection into the TMJ region did not "rekindle" the EMG activity, nor did the administration of the peripherally acting opiate antagonist methylnaloxone or the vehicle of naloxone. 3. These findings reveal that the application of the opiate antagonist naloxone produces a recurrence of increased jaw muscle activity reflexively evoked by mustard oil injection into the rat TMJ region. They suggest that central opioid depressive mechanisms activated by the mustard oil-induced afferent barrage limit the duration of the evoked EMG changes.


1991 ◽  
Vol 562 (1) ◽  
pp. 79-84 ◽  
Author(s):  
Geoffrey E. Gerstner ◽  
Louis J. Goldberg

2006 ◽  
Vol 157 (2) ◽  
pp. 285-293 ◽  
Author(s):  
Daraporn Sae-Lee ◽  
Kamal Wanigaratne ◽  
Terry Whittle ◽  
Christopher C. Peck ◽  
Greg M. Murray

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