Enhanced Ocular Surface and Intraoral Nociception via a Receptor Potential Vanilloid 1 Mechanism in a Rat Model of Obstructive Sleep Apnea
Obstructive sleep apnea (OSA) is a prevalent sleep disorder characterized by low arterial oxygen saturation during sleep. OSA has been associated with an increased risk of orofacial pain such as burning mouth syndrome and dry eye. In this study, Associate professor Ayano Katagiri and Professor Takafumi Kato, Department of Oral Physiology, Graduate School of Dentistry, have found the putative involvement of transient receptor potential vanilloid 1 (TRPV1) in mediating the intraoral and ocular surface pain in OSA, using an animal model. Rats subjected to chronic intermittent hypoxia (CIH) exhibited enhanced behavioral responses to capsaicin after application to the ocular surface and intraoral mucosa. Compared to normoxic rats, Rats subjected to CIH exhibited enhanced TRPV1-immunoreactivity in the neurons of the trigeminal ganglion and trigeminal spinal subnucleus caudalis. These effects recovered under normoxic conditions after CIH. These findings contribute to the comprehensive understanding of the underlying pathophysiology of non-odontogenic orofacial pain related to OSA.