Effects of central stimulants on onset of diaphragm activity during breath holding

Publisher Website
Google Scholar
Abstract
The effect of d-methylamphetamine, caffeine, and analeptics on the alveolar Pco2 during spontaneous breathing and at the onset of diaphragm activity during breath holding has been studied. After d-methylamphetamine the value of alveolar Pco2 at the onset of diaphragm activity, as well as at the breaking point, is significantly increased, while the ventilation-alveolar Pco2 relationship is not changed. After caffeine the value of the alveolar Pco2 at the onset of diaphragm activity, as well as at the breaking point, is significantly decreased and the ventilation-alveolar Pco2 relationship is significantly shifted to a lower Pco2. The value of alveolar Pco2 at onset of diaphragm activity is significantly decreased by prethcamide, increased by pentylenetetrazol, and not affected by dimefline. The ventilation-alveolar Pco2 relationship was not changed by such analeptics. These data, together with those previously obtained on hypoxia, suggest that factors changing the ventilation-alveolar Pco2 relationship also affect the onset of diaphragm activity, while the onset of diaphragm activity can be changed without affecting the ventilatory response to CO2. effect of analeptics on breath holding and on CO2 response curve; breaking point of breath holding; effect of caffeine on breath holding and on CO2 response curve; effect of d-methylamphetamine on breath holding and on CO2 response curve; ventilation-alveolar Pco2 relationship Submitted on July 5, 1963