Respiration Physiology 89 (1992) 157-167 © 1992 Elsevier Science Publishers B,V, All rights reserved, 0034-5687/92/$05.00
157
RESP 01932
Chemosensitivity and breathing pattern regulation of the coatimundi and woodchuck Dona F. Boggs ~, Conrad Colby b, Burl R. Williams, Jr. ~ and Delbert L. Kilgore, Jr. ~ aDivision of Biological Sciences. Uni,~rsiO' of Montana. Missoula. Montana. and ~Department of Respiratory Therapy. Boise State University. Boise. Idaho. USA (Accepted 13 April 1992) Abstract. An analysis of breathing pattern regulation was carried out on the coatimundi and woodchuck who represent two different volume-time patterns, it was found that the coati, with a short expiratory time as a fraction of total breath time, TE/TTOT, has a greater sensitivity to CO., as represented by the slope and threshold of its ventilatory response. Breathing air the coati maintains post-inspiratory inspiratory activity (PIIA) of the posterior ¢ricoarytenoid (PCA) through 51 ?o of expiration, while the woodchuck, who is less sensitive to CO: and has a long TE/TTOT, exhibits no PllA of the PCA. The woodchuck also has a greater incidence and duration of end-expiratory pauses (or delayed inspiratory onset). The woodchuck does not demonstrate the usual inverse relationship between VT and TE in response to 5/°!/, CO., and does not recruit PllA of the PCA at this level of CO.,. These data confirm the importance of CO: chemoscnsitivity in regulation of TB. It is further demonstrated that interspecific differences in chemosensitivity among three mammals of the same size are reflected in regulation of TB but not in inspiratory 'drive' (as indicated by mean inspiratory flow, VT/TI).
Chomosensitivity, pattern of breathing (Coatimundi ~:~ woodchuck); Mammals. coatimundi; Mammals. woodchuck; Pattern of~breathing, coatimundi t~ woodchuck
The coatimundi and woodchuck have quite difforont resting volume-time profiles and thus off`or an opportunity to test current theories about the control of breathing pattern. The coati has a relatively short expiratory time (TE) and the woodchuck a relatively long one (Boggs and Irvin, 1992). Boggs and Tenney (1984) demonstrated that the fraction of total breath time (TTOT) spent in inspiration (T0 tends to be an interspecific constant at 0.35, as is TE/TTOT at 0.65. The passive deflationary time constants of these two species are not significantly different
157
RESP 01932
Chemosensitivity and breathing pattern regulation of the coatimundi and woodchuck Dona F. Boggs ~, Conrad Colby b, Burl R. Williams, Jr. ~ and Delbert L. Kilgore, Jr. ~ aDivision of Biological Sciences. Uni,~rsiO' of Montana. Missoula. Montana. and ~Department of Respiratory Therapy. Boise State University. Boise. Idaho. USA (Accepted 13 April 1992) Abstract. An analysis of breathing pattern regulation was carried out on the coatimundi and woodchuck who represent two different volume-time patterns, it was found that the coati, with a short expiratory time as a fraction of total breath time, TE/TTOT, has a greater sensitivity to CO., as represented by the slope and threshold of its ventilatory response. Breathing air the coati maintains post-inspiratory inspiratory activity (PIIA) of the posterior ¢ricoarytenoid (PCA) through 51 ?o of expiration, while the woodchuck, who is less sensitive to CO: and has a long TE/TTOT, exhibits no PllA of the PCA. The woodchuck also has a greater incidence and duration of end-expiratory pauses (or delayed inspiratory onset). The woodchuck does not demonstrate the usual inverse relationship between VT and TE in response to 5/°!/, CO., and does not recruit PllA of the PCA at this level of CO.,. These data confirm the importance of CO: chemoscnsitivity in regulation of TB. It is further demonstrated that interspecific differences in chemosensitivity among three mammals of the same size are reflected in regulation of TB but not in inspiratory 'drive' (as indicated by mean inspiratory flow, VT/TI).
Chomosensitivity, pattern of breathing (Coatimundi ~:~ woodchuck); Mammals. coatimundi; Mammals. woodchuck; Pattern of~breathing, coatimundi t~ woodchuck
The coatimundi and woodchuck have quite difforont resting volume-time profiles and thus off`or an opportunity to test current theories about the control of breathing pattern. The coati has a relatively short expiratory time (TE) and the woodchuck a relatively long one (Boggs and Irvin, 1992). Boggs and Tenney (1984) demonstrated that the fraction of total breath time (TTOT) spent in inspiration (T0 tends to be an interspecific constant at 0.35, as is TE/TTOT at 0.65. The passive deflationary time constants of these two species are not significantly different
