Whole body plethysmography reveals differential ventilatory responses to ozone in rat models of cardiovascular disease

Breathing during the first postnatal hours has not been examined in mice, the preferred mammalian species for genetic studies. We used whole body plethysmography to measure ventilation (V˙e), breath duration (TTOT), and tidal volume (Vt) in mice delivered vaginally (VD) or by cesarean section (CS). In experiment 1, 101 VD and 100 CS pups aged 1, 6, 12, 24, or 48 h were exposed to 8% CO2 or 10% O2for 90 s. In experiment 2, 31 VD pups aged 1, 12, or 24 h were exposed to 10% O2 for 5 min. Baseline breathing maturation was delayed in CS pups, but V˙eresponses to hypercapnia and hypoxia were not significantly different between VD and CS pups [at postnatal age of 1 h (H1): 48 ± 44 and 18 ± 32%, respectively, in VD and CS pups combined]. TheV˙e increase induced by hypoxia was greater at H12 (46 ± 27%) because of TTOT response maturation. At all ages, hypoxic decline was ascribable mainly to a Vtdecrease, and posthypoxic decline was ascribable to a TTOTincrease with apneas, suggesting different underlying neuronal mechanisms.

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Measurement of respiratory function by whole body plethysmography in unanesthetized and unrestrained monkeys

Journal of Pharmacological and Toxicological Methods ◽

10.1016/j.vascn.2008.05.112 ◽

2008 ◽

Vol 58 (2) ◽

pp. 173

Author(s):

Kazuaki Sasaki ◽

Y. Nakamura ◽

H. Iizuka ◽

M. Imaizumi ◽

H. Atai

Keyword(s):

Respiratory Function ◽

Whole Body ◽

Body Plethysmography ◽

Whole Body Plethysmography

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Ventilatory behavior after hypoxia in C57BL/6J and A/J mice

Journal of Applied Physiology ◽

10.1152/jappl.2001.91.5.1962 ◽

2001 ◽

Vol 91 (5) ◽

pp. 1962-1970 ◽

Cited By ~ 42

Author(s):

Fang Han ◽

Shyam Subramanian ◽

Thomas E. Dick ◽

Ismail A. Dreshaj ◽

Kingman P. Strohl

Keyword(s):

Airway Resistance ◽

Minute Ventilation ◽

Genetic Effect ◽

Strain Differences ◽

Whole Body ◽

Environmental Forcing ◽

Ventilatory Responses ◽

Term Potentiation ◽

Genetic Mechanisms ◽

Whole Body Plethysmography

Given the environmental forcing by extremes in hypoxia-reoxygenation, there might be no genetic effect on posthypoxic short-term potentiation of ventilation. Minute ventilation (V˙e), respiratory frequency (f), tidal volume (Vt), and the airway resistance during chemical loading were assessed in unanesthetized unrestrained C57BL/6J (B6) and A/J mice using whole body plethysmography. Static pressure-volume curves were also performed. In 12 males for each strain, after 5 min of 8% O2 exposure, B6 mice had a prominent decrease inV˙e on reoxygenation with either air (−11%) or 100% O2 (−20%), due to the decline of f. In contrast, A/J animals had no ventilatory undershoot or f decline. After 5 min of 3% CO2-10% O2 exposure, B6 exhibited significant decrease in V˙e (−28.4 vs. −38.7%, air vs. 100% O2) and f (−13.8 vs. −22.3%, air vs. 100% O2) during reoxygenation with both air and 100% O2; however, A/J mice showed significant increase inV˙e (+116%) and f (+62.2%) during air reoxygenation and significant increase in V˙e (+68.2%) during 100% O2 reoxygenation. There were no strain differences in dynamic airway resistance during gas challenges or in steady-state total respiratory compliance measured postmortem. Strain differences in ventilatory responses to reoxygenation indicate that genetic mechanisms strongly influence posthypoxic ventilatory behavior.

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