September 4, 2012

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Coronal brain sections at P21 mice were immunostained with the anti-SNAP25 antibody. Intense SNAP25 immunoreactivity is observed in the insular and somatosensory cortices of brain sections from mice of "+ solid food" group. © Shinpei Kawakami

A research group at the Graduate School of Agricultural and Life Sciences, the University of Tokyo, collaborating with Morinaga & Co., Ltd., has discovered that signals resulting from the ingestion of solid food during weaning period promote a neural change in the cerebral cortex. Food intake stimuli are received by receptors in the oral cavity, and this information is transferred to the cerebral cortex. Signals from ingested food during the weaning period can affect synaptic transmission, resulting in biochemical changes in the cerebral cortex that modify gustatory and somatosensory nervous system plasticity. However, it remained unclear how these signals affect the change in the insular and somatosensory cortices.

The research group successfully determined that SNAP25 protein, a component of the presynaptic SNARE complex, increased in the insular and somatosensory cortices in weaning mice fed solid food but not in mice fed only mother’s milk at the weaning stage. Chemical stimulation by saccharin or capsaicin at the weaning stage also increased SNAP25 immunoreactivity in the insular and somatosensory cortical areas respectively. These results suggest that chemical signals in the oral cavity as a result of food ingestion during weaning increase the accumulation of SNAP25 in the gustatory and somatosensory cortices and promote neural plasticity during the development of these areas of the central nervous system.

This research outcome explains the mechanism by which ingestion of solid food influences neural development during weaning, and will be an important stimulus to further research.

Paper information

Shinpei Kawakami, Makoto Ohmoto, Shunsuke Ito, Reiko Yuasa, Hiroyuki Inagaki, Eisaku Nishimura, Tatsuhiko Ito, and Takumi Misaka, "Accumulation of SNAP25 in mouse gustatory and somatosensory cortices in response to food and chemical stimulation", Neuroscience, 218 (2012): 326-334, doi.:10.1016/j.neuroscience.2012.05.045.