STUDIES OF THE RESPIRATORY CENTER USING ISOLATED BRAIN-STEM-SPINAL CORD PREPARATIONS

It has been ten years since a brainstem-spinal cord preparation isolat ed from a newborn rat was introduced for study of the mammalian respir atory center. Here, I briefly summarize first, these studies, which in clude the tissue condition of in vitro preparations, respiratory refle xes, pharmacology, rhythm generation, respiratory chemoreception, phre nic motoneurons, regulation from pens, and development of a respirator y center. In the latter half of this paper, I focus on the neural mech anisms of respiratory rhythm generation. A current hypothesis for the central pattern generator of respiration proposed by the author's grou p is that the respiratory rhythm generator, composed of pre-inspirator y neurons in the rostral ventrolateral medulla, produces the primary r hythm of respiration and triggers an inspiratory pattern generator com posed of inspiratory neurons in the rostral and the caudal ventrolater al medulla.