Immunocytochemical localisation of NK3 receptors in the dorsal vagal complex of rat.

Using immunohistochemistry, we demonstrate that neurons of the rat dorsal vagal complex (DVC) express NK3 receptors. The density of NK3-immunoreactive neurons depends of the different subnuclei of the nucleus tractus solitarii. The efferent vagal neurons of the dorsal nucleus of the vagus nerve highly express NK3. No NK3-immunoreactivity has been detected in the area postrema. Ultrastructural examination shows that NK3-immunoreactivity is principally present at non synaptic membrane of somatic and dendritic profiles. Therefore, neurokinin B and/or other ligands may act through a process of volume transmission on non synaptic NK3 receptors in the DVC.