EFFECTS OF CHRONIC HYPOXIA ON THE SECRETORY RESPONSES OF RAT SALIVARY-GLANDS

Female Wistar rats were placed for 3 weeks in a simulated chamber evac uated by a vacuum pump and maintained at 40.5 kPa (7100 m). Dose-respo nse curves were obtained through the sequential injection, via the fem oral vein, of increasing doses of methacholine, methoxamine, isoprenal ine and substance P. The secretory activity in the parotid gland after exposure to chronic hypoxia was significantly decreased for all agoni sts studied, and the submaxillary gland showed the same behaviour exce pt in relation to isoprenaline, which did not show a significant diffe rence compared to controls. These data suggest that changes in the num ber or sensitivity of autonomic receptors and/or alterations in the in tracellular signals caused by hypoxia may be involved in the reduction in salivary secretory responses.