Chemical, electrical or physiological activation of cardiopulmonary vagal (cervical, thoracic
or cardiac), diaphragmatic vagal (DVAG) or subdiaphragmatic vagal (SDVAG) afferents can
result in either facilitation or inhibition of nociception in some species. In the rat, these effects
depend upon vagal afferent input to the NTS and subsequent CNS relays, primarily in the
NRM and ventral LC/SC, although specific relay nuclei vary as a function of the vagal
challenge stimulus. Spinal pathways and neurotransmitters have been identified for vagally …