抄録
Complaints of chronic pain patients may increase when the low-pressure system comes. We have demonstrated that artificially lowering the barometric pressure within the range of weather change intensifies pain-related behaviors in neuropathic rats. Furthermore, chemical destruction of inner ear organs inhibited this aggravating effect, suggesting that the barometric pressure sensors are located in the inner ear. In the present study, we extracellularly recorded neural activities in the vestibular nuclei with a glass microelectrode and examined the effect of lowering barometric pressure (LP, 40 hPa/ 8 min) in normal anesthetized rats. A set of stimuli (electrical stimulation of the vestibular nerve, rotation of the body or caloric test) was also applied to characterize neurons. Location of the neurons within the vestibular nuclei was histologically confirmed after the experiment. Five out of 17 recorded neurons increased their discharge frequency upon LP. There were three response patterns: 1) discharge rate increased along LP and vice versa, 2) discharge increased along LP but remained increased upon normalization of the pressure, 3) fluctuating discharge frequency was stabilized during LP. One neuron responded to the LP only, while others responded to one or more other stimuli (rotation or caloric test). Our present results indicate that the vestibular organs have an important role in detecting barometric pressure change. [J Physiol Sci. 2007;57 Suppl:S194]
