TY - JOUR
T1 - Alterations of hypoglossal motoneuronal activities during pulmonary inflations
AU - Hwang, Ji Chuu
AU - John, Walter M.St
N1 - Funding Information:
’ These studies were supported by grant 20574 from the National Heart, Lung and Blood Institute, National Institutes of Health. We thank Professor D. Rartlett, Jr. for his heIpfbI comments and Kurt V. Knuth for his development of computer &ware used in these studies Address correspondence to W. M. St. John, Department of Physiology, Dartmouth Medical School, Hanover, NH 03756.
PY - 1987/9
Y1 - 1987/9
N2 - Preventing pulmonary inflation during inspiration results in greater augmentations in activity of the hypoglossal nerve than in the phrenic nerve. Our purpose was to characterize the hypoglossal motoneuronal activities which underlie these augmentations. Activities of the phrenic and hypoglossal nerves and single hypoglossal fibers were recorded in decerebrate and paralyzed cats. Ventilation was by a servo-respirator which produced changes in lung volume in parallel with phrenic activity. The number of motoneurons that discharged during cycles in which the lungs were inflated increased with elevations of end-tidal fractional concentrations of CO2 (FETCO2) from 0.05 to 0.06 and 0.09. At each FETCO2, the discharge frequency increased when pulmonary inflation was withheld. In addition, withholding inflation resulted in the recruitment of other motoneuronal activities. Most motoneurons discharged during the period of the phrenic burst (inspiratory neurons). Lesser numbers of inspiratory-expiratory, expiratory-inspiratory, and tonic motoneuronal activities were also recorded. Results are considered in the context of the inhibition of respiratory motoneuronal activity by vagal pulmonary afferent fibers. The possible role of such inhibition, and release from this inhibition, in maintenance of patency of the upper airways is discussed.
AB - Preventing pulmonary inflation during inspiration results in greater augmentations in activity of the hypoglossal nerve than in the phrenic nerve. Our purpose was to characterize the hypoglossal motoneuronal activities which underlie these augmentations. Activities of the phrenic and hypoglossal nerves and single hypoglossal fibers were recorded in decerebrate and paralyzed cats. Ventilation was by a servo-respirator which produced changes in lung volume in parallel with phrenic activity. The number of motoneurons that discharged during cycles in which the lungs were inflated increased with elevations of end-tidal fractional concentrations of CO2 (FETCO2) from 0.05 to 0.06 and 0.09. At each FETCO2, the discharge frequency increased when pulmonary inflation was withheld. In addition, withholding inflation resulted in the recruitment of other motoneuronal activities. Most motoneurons discharged during the period of the phrenic burst (inspiratory neurons). Lesser numbers of inspiratory-expiratory, expiratory-inspiratory, and tonic motoneuronal activities were also recorded. Results are considered in the context of the inhibition of respiratory motoneuronal activity by vagal pulmonary afferent fibers. The possible role of such inhibition, and release from this inhibition, in maintenance of patency of the upper airways is discussed.
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U2 - 10.1016/0014-4886(87)90118-X
DO - 10.1016/0014-4886(87)90118-X
M3 - Article
C2 - 3622714
AN - SCOPUS:0023199629
SN - 0014-4886
VL - 97
SP - 615
EP - 625
JO - Experimental Neurology
JF - Experimental Neurology
IS - 3
ER -