TY - JOUR
T1 - Dynamic profile of cardiovascular activity in relation to augmented ventilation and humoral agents during hypercapnic hypoxia.
AU - Tanaka, M.
AU - Takaishi, S.
AU - Ohdaira, T.
AU - Kobayashi, T.
AU - Maruyama, R.
AU - Ahn, B.
AU - Masuda, A.
AU - Masuyama, S.
AU - Honda, Y.
PY - 1991
Y1 - 1991
N2 - A time course of cardiovascular activity in 8 healthy males in relation to augmented ventilatory activity and humoral factors was observed during step CO2 elevation with constant hypoxia. During the first step increase, by 3 Torr in end-tidal PCO2 (PETCO2), the heart rate (HR) initially tended to decrease, then slowly increased to slightly below that of the previous eucapnic level, whereas ventilation maintained a gradual rise throughout this period. On the other hand, during second step PETCO2 elevation, by a further 3 Torr, both HR and ventilation progressively increased. The plasma catecholamine (CA) concentration was also significantly elevated during this period, suggesting a concomitant enhancement in sympathetic activity. Blood pressure (Bp) was progressively augmented throughout the entire hypoxic challenge. We conclude that 1) the characteristic profile of HR change may be explained by the observation that initial HR depression by peripheral chemoreceptor stimulation is gradually overridden by delayed hyperventilation, CA elevation, and enhanced sympathetic activity; 2) Bp augmentation may be elicited by increased CA release and sympathetic activity; and 3) plasma K+ concentration does not change so as to affect cardiovascular and respiratory activity.
AB - A time course of cardiovascular activity in 8 healthy males in relation to augmented ventilatory activity and humoral factors was observed during step CO2 elevation with constant hypoxia. During the first step increase, by 3 Torr in end-tidal PCO2 (PETCO2), the heart rate (HR) initially tended to decrease, then slowly increased to slightly below that of the previous eucapnic level, whereas ventilation maintained a gradual rise throughout this period. On the other hand, during second step PETCO2 elevation, by a further 3 Torr, both HR and ventilation progressively increased. The plasma catecholamine (CA) concentration was also significantly elevated during this period, suggesting a concomitant enhancement in sympathetic activity. Blood pressure (Bp) was progressively augmented throughout the entire hypoxic challenge. We conclude that 1) the characteristic profile of HR change may be explained by the observation that initial HR depression by peripheral chemoreceptor stimulation is gradually overridden by delayed hyperventilation, CA elevation, and enhanced sympathetic activity; 2) Bp augmentation may be elicited by increased CA release and sympathetic activity; and 3) plasma K+ concentration does not change so as to affect cardiovascular and respiratory activity.
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U2 - 10.2170/jjphysiol.41.617
DO - 10.2170/jjphysiol.41.617
M3 - Article
C2 - 1791662
AN - SCOPUS:0026276597
VL - 41
SP - 617
EP - 627
JO - The Journal of Physiological Sciences
JF - The Journal of Physiological Sciences
SN - 1880-6546
IS - 4
ER -