Present address: Département d'Anatomie et de Physiologie, Faculté de Médecine, Université Laval, Québec (Qué), CANADA, G1K 7P4.
Contribution of the vagus nerve and lamina terminalis to brain activation induced by refeeding
Article first published online: 27 SEP 2005
European Journal of Neuroscience
Volume 22, Issue 6, pages 1489–1501, September 2005
How to Cite
Timofeeva, E., Baraboi, E. D. and Richard, D. (2005), Contribution of the vagus nerve and lamina terminalis to brain activation induced by refeeding. European Journal of Neuroscience, 22: 1489–1501. doi: 10.1111/j.1460-9568.2005.04330.x
- Issue published online: 27 SEP 2005
- Article first published online: 27 SEP 2005
- Received 19 April 2005, revised 6 July 2005, accepted 11 July 2005
Following refeeding, c-fos expression is induced in a particular set of brain regions that include the nucleus of the solitary tract (NTS), parabrachial nucleus (PB), central amygdala (CeA), paraventricular hypothalamic nucleus (PVH), supraoptic nucleus (SON) and the circumventricular organs. Within the PVH, the expression is particularly intense in the magnocellular division of the nucleus and it is as yet not clear how this activation occurs. The respective contribution of the vagus afferents and lamina terminalis, which conveys signals entering the brain through the forebrain circumventricular organs, has been investigated in rats subjected to a unilateral cervical vagotomy (UCV) or a unilateral lesion of the fibres running within the lamina terminalis (ULT) and projecting to the neuroendocrine hypothalamus. UCV significantly decreased postprandial c-fos expression in the NTS, PB, CeA and parvocellular division of the PVH. In contrast, ULT impaired postprandial activation of the magnocellular neurons in the PVH and SON. The present study also characterized the types of neurons activated in the PVH and SON during refeeding. In the magnocellular regions, arginine-vasopressin (AVP) neurons were activated upon refeeding whereas there was no apparent induction of Fos expression in oxytocin cells. In the parvocellular PVH, postprandial Fos was induced only in 30% of the corticotrophin-releasing factor (CRF) and AVP neurons. The results of the present study suggest that the postprandial activation of the brain requires the integrity of both the vagal- and lamina terminalis-associated pathways.