[Possible existence of spinal inspiratory activity in the in vitro brain stem-spinal cord preparation from newborn rats].

Summing up with classical shortlasting inspirations, periodic longlasting inspirations (approximately 10 s) may be recorded with the normal inspirations through plethysmographic method in the intact newborn rat under deep diethyl ether anaesthesia. When they are present in vivo, the fast brainstem-spinal cord isolation allows to record in vitro periodic longlasting motor bursts (10-25 s) on C2-C8 ventral roots adding to shortlasting respiratory bursts (1-3 s) on C1-T13 ventral roots. Both kinds of rhythmic activities display a synchronous bilateral pattern. The longlasting bursts are maintained after a C2 spinal transection, especially if they have been induced by phenylephrine hydrochloride superfusion (0.4-0.5 mM).