Recent advances in respiratory neurobiology using in vitro methods.

Major advances in our understanding of the neurobiology of respiration are occurring due to the advent of mammalian in vitro preparations. These preparations include whole mounts of brain stem and spinal cord of the neonatal rat, thick and thin slices from various parts of the central nervous system (CNS), and isolated cells. A great advantage of such preparations is the ability to control precisely the extracellular environment and, by means of patch-type electrodes, the intracellular environment as well. Such control enables both membrane and intracellular mechanisms to be determined, thereby providing new insights into a variety of neuronal behaviors important to respiration. These behaviors include respiratory rhythmogenesis, the effect of intrinsic mechanisms on firing patterns, direct effects of neurotransmitters, and chemoreception. This commentary discusses these preparations and shows how they have recently been used to make major advances in our understanding of respiratory neurobiology.