Contribution Of Glutamatergic Vestibulo-visceral Pathways To Response Of Autonomic Nervous System During Motion Sickness In Rats

The contribution of glutamate (Glu) to the autonomic responses during motion sickness remained unclear. The present study was designed to investigate role of glutamatergic vestibular nuclei (VN) neurons in autonomic response during motion sickness in rats by using methods of ethology, tract tracing combined to immunofluorescence histochemistry and further examine the regulation of vestibulo-autonomic pathways on cardiovascular system by physiological method. It was found that motion stimuli elicited apparent behavior changes related to disorders of autonomic nervous system and induced significant Fos expression in caudal VN and autonomic nuclei in brain stem. The existence of glutamatergic VN-NTS and VN-PBN pathways were also confirmed and these two pathways were activated during motion stimulation. We also found that NMDA receptor blockade by MK-801 attenuated pressor effect evoked by L-Glu injected into MVe. It was concluded that glutamatergic vestibulo-visceral pathways play an important role in response of autonomic nervous system during motion sickness. NMDA receptor involved in primary vestibular signal transmission during regulation of cardiovascular funtion.