Substance P-immunoreactivity in the dorsal medial region of the medulla in the cat: effects of nodosectomy.
The distribution of substance P in the vagal system of the cat was studied by immunohistochemistry. Substance P-immunoreactive cell bodies and fibres were observed in the nodose ganglion. Numerous substance P-immunoreactive terminals and fibres were localized in their bulbar projection area, i.e. throughout the caudo-rostral extent of the nucleus of the solitary tract. Four subnuclei, among the nine forming the nucleus of the solitary tract, were strongly labelled: interstitial, gelatinosus, dorsal and commissural. The dorsal motor nucleus of the vagus nerve also exhibited numerous substance P-immunoreactive terminals, sometimes closely apposed on the somata of preganglionic neurons. To determine the substance P component of the vagal afferent system a nodose ganglion was removed on one side. The ablation triggered ipsilaterally a large decrease of substance P immunoreactivity in the four subnuclei strongly labelled on normal cats. These results suggest the involvement of substance P-containing vagal fibres in integrative processes of the central regulation of cardiovascular, digestive and respiratory systems, viscerotopically organized throughout these four subnuclei. The nodose ablation also resulted in a decrease of substance P immunoreactivity in the ipsilateral dorsal motor nucleus of the vagus nerve, suggesting monosynaptic vago-vagal interactions.
Baude
A
A
CNRS, Laboratoire de Neurobiologie, Marseille, France.
Lanoir
J
J
Vernier
P
P
Puizillout
J J
JJ
D000818:Animals; D002415:Cats; D003714:Denervation; D005260:Female; D007124:Immunoenzyme Techniques; D008297:Male; D008526:Medulla Oblongata / Q000032:analysis* / Q000033:anatomy & histology; D009620:Nodose Ganglion / Q000502:physiology*; D013373:Substance P / Q000032:analysis*; D014630:Vagus Nerve / Q000032:analysis / Q000502:physiology*
D013373:Substance P