Oxytocin-immunoreactive innervation of identified neurons in the rat dorsal vagal complex
Article first published online: 21 DEC 2011
© 2011 Blackwell Publishing Ltd
Neurogastroenterology & Motility
Volume 24, Issue 3, pages e136–e146, March 2012
How to Cite
Llewellyn-Smith, I. J., Kellett, D. O., Jordan, D., Browning, K. N. and Alberto Travagli, R. (2012), Oxytocin-immunoreactive innervation of identified neurons in the rat dorsal vagal complex. Neurogastroenterology & Motility, 24: e136–e146. doi: 10.1111/j.1365-2982.2011.01851.x
- Issue published online: 8 FEB 2012
- Article first published online: 21 DEC 2011
- Received: 9 June 2011 Accepted for publication: 25 November 2011
- dorsal motor nucleus of the vagus;
- nucleus of the solitary tract;
- tyrosine hydroxylase;
Background Oxytocin (OXT) has been implicated in reproduction and social interactions and in the control of digestion and blood pressure. OXT-immunoreactive axons occur in the dorsal vagal complex (DVC; nucleus tractus solitarius, NTS, dorsal motor nucleus of the vagus, DMV, and area postrema, AP), which contains neurons that regulate autonomic homeostasis. The aim of the present work is to provide a systematic investigation of the OXT-immunoreactive innervation of dorsal motor nucleus of the vagus (DMV) neurons involved in the control of gastrointestinal (GI) function.
Methods We studied DMV neurons identified by (i) prior injection of retrograde tracers in the stomach, ileum, or cervical vagus or (ii) induction of c-fos expression by glucoprivation with 2-deoxyglucose. Another subgroup of DMV neurons was identified electrophysiologically by stimulation of the cervical vagus and then juxtacellularly labeled with biotinamide. We used two- or three-color immunoperoxidase labeling for studies at the light microscopic level.
Key Results Close appositions from OXT-immunoreactive varicosities were found on the cell bodies, dendrites, and axons of DMV neurons that projected to the GI tract and that responded to 2-deoxyglucose and juxtacellularly labeled DMV neurons. Double staining for OXT and choline acetyltransferase revealed that OXT innervation was heavier in the caudal and lateral DMV than in other regions. OXT-immunoreactive varicosities also closely apposed a small subset of tyrosine hydroxylase-immunoreactive NTS and DMV neurons.
Conclusions & Inferences Our results provide the first anatomical evidence for direct OXT-immunoreactive innervation of GI-related neurons in the DMV.