Angiotensin II-induced rhythmic jaw movements in the ketamine-anesthetized guinea pig.
ABSTRACT The EMG activity of the left anterior digastric muscle as well as associated jaw movements were studied in ketamine-anesthetized guinea pigs that had received i.v. infusions of angiotensin II (ANG-II). Rhythmic jaw movements with two distinct movement profiles were associated with ANG-II infusion. One movement profile was typified by vertical jaw opening and closing movements with little or no associated horizontal movement. The second rhythmical jaw movement profile was unlike the first in that jaw closing was accompanied by a significant horizontal deflection of the jaw. Both jaw movement profiles were similar in that little or no horizontal movement occurred during jaw opening. Tongue protrusions were also observed during jaw opening in both cases. The results show that ANG-II induces rhythmic jaw movements in anesthetized guinea pigs. ANG-II-induced jaw movement profiles and digastric muscle EMG activity are similar to those seen after an i.v. injection of apomorphine in the anesthetized guinea pig, and to those associated with lapping in the awake animal.
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ABSTRACT: Introduction Bruxism is an unusual event among patients of altered sensorium after brain injury. Occasionally the bruxism may be so severe as to cause harm to the patients and make nursing difficult. This study presents such cases that were managed by the author. A possible explanation for post-brain injury bruxism is suggested. Material and method Twelve patients of brain injury following trauma who were observed to have bruxism were included in the study. The clinical presentation and the response to intervention were studied. Patients less then 16 years were managed with benzodiazepines only. Patients more than 16 years of age were managed with benzodiazepines and pramipexole was administered in addition to benzodiazepines in 5 patients. Observation Of the 12 patients 3 subjects were classified as severe brain injury. Nine patients had suffered moderate grade brain injury. 3 (25%) patients were children and the mean age of the rest 9 (75%) patients was 40 years. The children were managed with benzodiazepines. The median time of onset of bruxism from the time of injury was 5.25 days with range of 2 days–12 days. Pramipexole, a dopamine agonist, was useful in management of severe bruxism with a latency period of 2 days. All patients except one recovered within 7 days after starting the treatment. Conclusion Bruxism is distressing to a patient-in-recovery following brain injury and cause significant inconvenience to the nursing staff. Effective treatment included the use of benzodiazepines and pramipexole. Pramipexole, a dopamine receptor agonist, should be considered an option for pharmacological management of bruxism after brain trauma. If central pattern generators (CPG) are involved in some of the disabilities of moderate to severe brain injuries like bruxism, there is a rationale for considering a larger study for the use of dopamine receptor agonist in such patients.06/2014; DOI:10.1016/j.ijnt.2014.02.002
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ABSTRACT: This study tested a system for monitoring jaw movements in freely moving rats. A Hall-effect transducer was fixed to the skull in order to sense voltage changes induced by variations in the position of a magnet fixed to the mandible. By measuring dopamine receptor-mediated jaw movements, this system produces data comparable to that obtained using a light-sensitive transducer system in anesthetized rats, while also measuring the vertical component of jaw movements in freely moving rats. In combination with conventional visual observation, this system may provide a useful tool for assessing movements of the orofacial region during spontaneous and drug-evoked behavior.Methods and Findings in Experimental and Clinical Pharmacology 09/2003; 25(7):525-30. DOI:10.1358/mf.2003.25.7.778091 · 0.77 Impact Factor