Modulation of Glycinergic Inhibition on Respiratory Rhythmic Hypoglossal Bursting in the Rat

Kun-Ze Lee ； Ji-Chuu Hwang

《The Chinese Journal of Physiology》 62卷1期 (2019/02) Pp. 27-34

https://doi.org/10.4103/CJP.CJP_10_18

摘要

The hypoglossal nerve displays respiratory rhythmic bursting and is composed of preinspiratory and inspiratory activity which is important in maintaining upper airway patency. The present study was designed to examine the modulatory role of glycinergic inhibition in respiratory rhythmic hypoglossal bursting. The activity of the phrenic nerve, as well as the medial and lateral branches of the hypoglossal nerve, was recorded simultaneously in urethane-anesthetized and mechanically ventilated adult rats in response to moderate and high levels of sustained lung inflation. The results demonstrated that inspiratory activity of the phrenic nerve gradually reduced with increasing lung inflation. The burst amplitude and discharge onset of the hypoglossal nerve branches were enhanced during moderate lung inflation but inhibited by high levels of lung inflation. These lung volume-mediated respiratory reflexes were abolished following a bilateral cervical vagotomy. In addition, intravenous administration of a glycine receptor antagonist (strychnine, 1 μmole/kg) attenuated preceding onset of rhythmic hypoglossal bursting but enhanced inspiratory hypoglossal burst amplitude during the baseline. Moreover, both excitatory and inhibitory effects of lung inflation on hypoglossal nerve activity were attenuated following a glycine transmission blockade. These results suggest that glycinergic inhibition modulated rhythmic hypoglossal bursting and was involved in mediating lung volume-induced respiratory reflexes.

關鍵字

Glycinergic inhibition ； hypoglossal ； lung inflation

參考文獻

Lee KZ, Fuller DD, Lu IJ, Lin JT, Hwang JC. Neural drive to tongue protrudor and retractor muscles following pulmonary C‑fiber activation. J Appl Physiol (1985) 2007;102:434-44.

Lee KZ. Phrenic motor outputs in response to bronchopulmonary C‑fibre activation following chronic cervical spinal cord injury. J Physiol 2016;594:6009-24.

Ezure K, Tanaka I, Saito Y. Activity of brainstem respiratory neurones just before the expiration-inspiration transition in the rat. J Physiol 2003;547:629-40.

Bartlett D Jr., St. John WM. Adaptation of pulmonary stretch receptors in different mammalian species. Respir Physiol 1979;37:303-12.

Lee LY, Yu J. Sensory nerves in lung and airways. Compr Physiol 2014;4:287-324.