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Genioglossal recruitment during acute hypoxia and hypercapnia in kittens
Author(s) -
Watchko Jon F.,
Klesh Kenneth W.,
O'Day Terrence L.,
Weiss Marc G.,
Guthrie Robert D.
Publication year - 1989
Publication title -
pediatric pulmonology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.866
H-Index - 106
eISSN - 1099-0496
pISSN - 8755-6863
DOI - 10.1002/ppul.1950070409
Subject(s) - hypercapnia , hypoxia (environmental) , medicine , diaphragmatic breathing , anesthesia , respiratory system , oxygen , chemistry , pathology , alternative medicine , organic chemistry
We examined genioglossal and diaphragmatic EMG activities in one‐ and two‐month‐old anesthetized kittens during acute exposures to hypoxic (13% or 10% O 2 ) and hyperoxic hypercapnic (8% CO 2 /50% CO 2 /balanced N 2 ) gas mixtures. Phasic genioglossal EMG activity, frequently characterized by a combined inspiratory‐expiratory discharge pattern, was observed in 3 of 8 one‐month‐old vs. 7 of 7 two‐month‐old kittens during hypercapnia (Chisquare P <0.05). The percentage of kittens recruiting genioglossal activity during hypoxic exposures was similar at both ages (1 month, 75%; 2 month, 83%). Analysis of the breath‐by‐breath response during trials of hypoxia in which genioglossal recruitment was observed, however, revealed that the one‐month‐old kittens exhibited phasic genioglossal activity in only 40±27% of the stimulated breaths, compared to 63±26% for the two‐month‐old ones ( P <0.05) at each level of hypoxia. In this regard, the genioglossal response to hypoxia in one‐month‐old kittens was frequently characterized by early and only transient recruitment (when diaphragmatic activity was at its peak), while genioglossal recruitment was more sustained in two‐month‐old animals. These data indicate that genioglossal activity in kittens is often recruited during exposures to hypercapnia and hypoxia, and suggest that such recruitment is more frequent with increasing postnatal age. Pediatr Pulmonol 1989; 7:235–243 .