Dynamics of respiratory VT response to isocapnic pHa forcing in chemodenervated cats

Publisher Website
Google Scholar
Abstract
Arterial blood pH (pHa) was continuously monitored in decerebrate or pentobarbital-anesthetized cats with a rapidly responding H+ sensor inserted into the aorta. Alveolar CO2 partial pressure and pHa were controlled independently during infusions of 1 N NaHCO3 or 0.5 HCl into the inferior vena cava. Shifts in pHa up to 0.3 unit were effected isocapnically within 2.5-20 s over a working pHa range of 6.9-7.7. Before carotid sinus neurotomy, average onset latency of the tidal volume (VT) response to acid and alkaline pHa shifts was less than 5 s and the average VT response half time was less than 8.5 s regardless of whether the vagus nerves had been interrupted. After carotid sinus neurotomy, the .DELTA.VT onset latency was approximately doubled, whereas the response half time was prolonged about eightfold on the average. Subsequent vagotomy tended further to increase the responding time lag. The minimum response latency after peripheral chemodenervation was less than the .DELTA.pHa forcing rise time. The central chemoreceptors apparently promptly sense pH change in the arterial blood and neural processes adjust the time course of the respiratory response through the VT controller.

This publication has 5 references indexed in Scilit: