ABSTRACT
The nucleus tractus solitarii (NTS) is the primary site of integration of afferent inputs relayed in the IXth and Xth cranial nerves and, as such, is involved in gastrointestinal, respiratory, and cardiovascular function. This chapter reviews the role of the NTS in the integrative functions, but will restrict consideration to the area of cardiovascular control where there appears to be a more established background literature. There is evidence in the literature indicating that the arterial chemoreceptor reflex is able to induce the autonomic and respiratory features of the defense reaction in the althesin-anesthetized cat and rat. The arterial chemoreceptors are known to provide an excitatory input to nonrespiratory neurones located in dorsal aspects of the NTS rostral and caudal to the obex particularly within the medial and commissural subnuclei. The pattern of interaction revealed suggests that those NTS neurones that are mono- or disynaptically excited by baroreceptor inputs are under the control of a group of γ-aminobutyric acid-containing neurones.
