Neurochemical organization of paratrigeminal nucleus projections to the dorsal vagal complex in the rat

The paratrigeminal nucleus, located in the spinal trigeminal tract rostral to the obex, is important in the integration of visceral and somatosensory afferent information and may modulate autonomic function through its projections to the dorsal vagal complex. Anterograde and retrograde neuroanatomical tracers were used in conjunction with immunohistochemistry to determine the neurochemical organization of the efferent pathway from the paratrigeminal nucleus to the dorsal vagal complex in the rat. Double-labelling studies demonstrated that leu-enkephalin, 28-kDa calbindin, and neuronal nitric oxide synthase were present in neurons in the paratrigeminal nucleus that project to the dorsal vagal complex. The results of this study are consistent with the hypothesis that neurochemically distinct pathways from the paratrigeminal nucleus are involved in the sensory modulation of autonomic function. (C) 1998 Elsevier Science B.V.