Neural circuits controlling cardiorespiratory responses: baroreceptor and somatic afferents in the nucleus tractus solitarius.

Abstract

1. A vast array of peripheral receptors provide the central nervous system (CNS) with sensory signals that coordinate autonomic motor outflow to cardiovascular organs, such as the heart and peripheral vasculature, during locomotion. 2. Much of this sensory input is mediated by cardiovascular receptors located in blood vessels (arterial baroreceptors) and skeletal muscle (skeletal muscle ergoreceptors). 3. Several medullary nuclei are targets for cardiovascular receptors, including the nucleus tractus solitarius (NTS). 4. In the present review, the interaction between arterial baroreceptor and somatosensory receptor afferents in the NTS is examined while placing particular emphasis on the neurochemical and electrophysiological mechanisms involved in processing these signals. 5. Data from anaesthetized animals, as well as from an innovative working heart-brainstem preparation, will illustrate the potential role of GABAergic transmission on baroreceptor signalling in the caudal NTS during locomotion.