PAROTID SECRETION DAILY PATTERNS AND MEASUREMENT WITH ULTRASONIC FLOWPROBES IN CONSCIOUS SHEEP

Five sheep under halothane anesthesia were prepared with bilateral tra nsit time ultrasonic flow probes around the parotid ducts. The ducts w ere fitted with non-obstructive sampling catheters through their oral ends. After probe encapsulation (8 days), salivary flows were continuo usly recorded (4-5 days, dual-channel ultrasonic flowmeter). For rumin ation, eating, resting and drinking periods, respectively, the parotid daily outputs recorded were 1.96 +/- 0.57, 0.97 +/- 0.34, 2.84 +/- 0. 41 and < 0.041 and bilateral flow rates were 6.76 +/- 0.70, 5.63 +/- 1 .42, 2.50 +/- 0.58 and 1.69 +/- 0.88 ml min(-1). An ipsilateral secret ory reflex was evident when the sheep changed chewing side during rumi nation (4.44 +/- 0.96 mi min(-1) ipsilateral vs. 2.63 +/- 0.90 mi min( -1) contralateral flow, P < 0.01). Secretory patterns are described in detail during rest, eating, drinking and rumination periods. The pH o f parotid saliva (8.36 +/- 0.14) and the osmolality (273.8 +/- 9.9 mos mol kg(-1)) were independent of secretory rates. In situ probe calibra tion showed high accuracy (0-9%). The main advantages of the technique are its accuracy and good tolerance, duct integrity and maintenance o f nervous supply, minimal surgery uninterrupted salivary flow, simulta neous bilateral measurements and precise flow monitoring, permitting d etailed observations.