[The postnatal development of EMG reactions of limb muscles to free fall stimulation. II. Studies of early postnatal hypoxic-burdoned rabbits].

12 rabbits ("Deutscher Riese") were exposed to a hypoxic atmosphere (FiO2 = 0.05) for 3 h at their 1st day of life. At the 7th or 13th day of life, steel wire electrodes were chronically implanted into 3 leg muscles in order to record the electromyograms (EMG). The myographic activity was derived during free fall (height of drop = 0.5 m) until the age of 20 days. The quantitatively analysed EMG data were compared with corresponding data of undisturbed growing control animals. Using various EMG parameters, a quantitative separation of hypoxic animals from the controls was successfully done by a discriminant analysis, the animals being 8 and 20 days of age, respectively. It can be concluded that 1. already a single perinatal hypoxic load influences the supraspinal motor system permanently at least up to the age of 20 days, and that 2. this supraspinal influence on the investigated vestibulospinal reaction changes with increasing age of the rabbits.