TIME DOMAINS OF THE HYPOXIC VENTILATORY RESPONSE

The ventilatory response to hypoxia depends on the pattern and intensi ty of hypoxic exposure and involves several physiological mechanisms. These mechanisms differ in their effect (facilitation or depression) o n different components of ventilation (tidal volume and frequency) and in their time course (seconds to years). Some mechanisms last long en ough to affect future ventilatory responses to hypoxia, indicating 'me mory' or functional plasticity in the ventilatory control system. A st andard terminology is proposed to describe the different time domains of the hypoxic ventilatory response (HVR) and to promote integration o f results from different experimental preparations and laboratories. I n general, the neurophysiological and neurochemical basis for short ti me domains of the HVR (seconds and minutes) are understood better than longer time domains (days to years), primarily because short time dom ains are studied in the laboratory more easily. Understanding the mech anisms for different time domains of the HVR has important implication s for both basic and clinical science. (C) 1998 Elsevier Science B.V. All rights reserved.