Journal of Applied Physiology, Vol 56, Issue 2 321-325, Copyright © 1984 by American Physiological Society
Postnatal maturation of ventilation and breathing pattern in kittens: influence of sleep
D. Marlot, M. Bonora, H. Gautier and B. Duron
Ventilation and breathing pattern were studied in kittens at 1, 2, 3, 4,
and 8 wk of life during quiet wakefulness (W), quiet sleep (QS), and active
sleep (AS) with the barometric method. Tidal volume (VT), respiratory
frequency (f), ventilation (VE), inspiratory time (TI), expiratory time
(TE), mean inspiratory flow (VT/TI), and respiratory "duty cycle" (TI/TT)
were measured. VT, VE, TI, TE, and VT/TI increased; f decreased and TI/TT
remained constant during postnatal development in wakefulness and in both
sleep states. No significant difference was observed between AS and QS for
all the ventilatory parameters except TI/TT, which was greater in QS than
in AS at 2 wk. VE was larger in W than in both AS and QS at all ages. This
was mainly due to a greater f, TI/TT remaining constant. VT/TI, which
represents an index of the central inspiratory activity, was larger in W
than in sleep, VT not being significantly different whatever the stage of
consciousness. The results of this study show that in the kitten 1) unlike
in the adult cat, ventilation and breathing pattern are similar in QS and
in AS; 2) in sleep, the central inspiratory drive appears to be independent
of the type of sleep; and 3) in wakefulness, the increase of the central
inspiratory activity could be related to important excitatory inputs.
