Unilateral nasal resistance and asymmetrical body pressure.

Lateral recumbency causes ipsilateral nasal congestion and contralateral decongestion. Nasal resistances were measured before, during and after the application of pressure either regionally or by lateral recumbency. In some experiments an attempt was made to block the response by local anesthetic injection, splinting the nasal vestibules, or topical decongestants. In others an electric blanket was employed as a stimulus instead of pressure. It was concluded that the nasal resistance changes during lateral recumbency are due to pressure receptors in the pelvic and pectoral girdles, and thorax. These adapt slowly. They are probably situated in the intercostal spaces, parietal pleura, or sterno-costal joints. Their centripetal fibers probably travel in the intercostal nerves, and their efferents in the cervical sympathetic outflow to the nasal erectile tissue. Lateral recumbency of 12 minutes' duration induces changes in nasal resistance which persist after the pressure asymmetry has been terminated. This may be due to temporal summation.