ラット自由行動下における舌筋活動の筋電図学的研究
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概要
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The present study was carried out to compare the characteristics of EMG activites of the anterior and posterior parts of the tongue and to investigate changes of EMG activities of these parts after the severance of the lateral or medial branches of the hypoglossal nerves in the rat. Bipolar electrodes of 50 μm stainless steel wire coated with Teflon^[○!R] were placed internally on the muscles of the anterior and posterior parts of the tongue and led to a connector fixed on the center of the cranial bone. In recording EMG, the terminal of connector and the amplifier were connected with other thin wires and rat could move and eat freely in the cage. Control EMG was recorded after 3 and 7 days from setting the electrodes and a connector. The postoperative EMG was recorded after 3 and 7 days from severance of the lateral or medial branches of both sides of the hypoglossal nerves. EMG pattern and muscle activities that were indicated as 100, relative value of integrated value of EMG during feeding, in the anterior and posterior parts of the tongue, and those after severance of the lateral and medial branches were compared. The main findings were summarized as follows. 1. During feeding of intact rats, several small amplitude bursts were generated when the biting sound by incisor was heard, and immediately about 20 bursts with semilarge amplitude and brief interval, and following rhythmical bursts when rat masticated with molar were elicited. The rhythmical bursts of the anterior and posterior parts were composed of burst generated with semilarge and large amplitude alternately. The freguency of burst of the anterior parts was twice that of the posterior parts. 2. The cycle of rhythmical bursts of the posterior parts during mastication was about 214 msec. On the other hand, the cycle (C2, C3) from first burst (A1) to next first burst (A1), and from second burst (A2) to next second bursts (A2) were bout 214 msec. The interval (I1, I2) from A1 to A2 and from A2 to A1 were 91 and 114 msec respectively. 3. The hythmical bursts of the posterior parts during mastication always preceded slightly those of the anterior parts. The time lag (P-A1, P-A2) from burst of the postrior part and first bursts (A1), and to second bursts (A2) of anterior parts were about 14, and 105 msec. The duration of semilarge and large bursts were same and about 100 msec. The duration of A1 and A2 of the anterior part were about 54 and 76 msec. The A1 and A2 differed in amplitude and duration of the rhythmical bursts during chewing. 4. EMG patterns of the anterior and posterior parts during licking differed. EMG pattern of the anterior parts was almost rhythmical. The cycle and duration of the anterior parts were about 162 and 106 msec and shorter than those during mastication. 5. After severance of both the lateral branches of the hypoglossal nerves, EMG pattern did not change, but cycle of the anterior and posterior parts was shortened significantly and the time lag of the posterior and anterior parts, too. 6. After severance of both the medial branches of the hypoglossal nerves, rhythmical bursts during feeding disappeared and bursts with small amplitude continued. The rhythmical bursts of the posterior and anterior parts during grooming reduced and those during licking were shortened in time elicited and irregular. 7. In intact rat, the muscle activities of the posterior parts during feeding, grooming, licking, exploring, and resting were 100, 110, 107, 63 and 37, and those of the anterior parts, 100, 128, 132, 65 and 36, respectively. The muscle activities during these behavior after severance of lateral and medial branches reduced about 29∿56% and 7∿40%.
- 九州歯科学会の論文
- 1994-02-25
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関連論文
- ラット自由行動下における舌筋活動の筋電図学的研究 : 主論文の要旨
- ラット自由行動下における舌筋活動の筋電図学的研究
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