P822

         Physiol Bohemoslov 1976;25(2):159-66

        Pattern of breathing in the rat.

        Paleček F, Chválová M.

        The basic ventilation values - tidal volume (VT), breathing frequency

        (f), minute ventilation (VE) and the duration of inspiration (TI) and

        expiration (TE) -- were determined in adult male rats. The range of

        these values is given and the pattern of breathing is defined as the

        relationship between VE and VT, which in the rat is linear throughout

        its entire range. The role of TI and TE in changing f in the rat were

        evaluated. The breathing pattern of the rat was compared with data for

        the rabbit and man, using percentual expression of the basic values. A

        shift of the breathing pattern to higher f values was observed in rats

        with experimental lung diseases. In these rats, the inhalation of 100%

        O2 shifted the pattern of breathing markedly to lower VE values, though

        not to values comparable with the controls. Bilateral cervical vagotomy

        was followed by a pronouced decrease in f, an increase in VT and T1

        persisted even after vagotomy, however; it can be assumed that this

        relationship is effected either by means of receptors in the chest

        muscles, or by the direct action of CO2 which is used to stimulate

        breathing, on the bulbopontine pacemaker.