| Abstract: | A study was initiated to ascertain whether gaseous air pollutants can influence gastric secreto-motor activities. The investigation was conducted to determine the effect of various exposures to S02, N02, CO, and 03 on gastric motor activity of the conscious unrestrained rat by means of a chronic intragastric bajloon. Tfie effects produced upon gastric secretory volume and total titratable acid secretion produced by these gases were also studied in rats which were pylorus-ligated subsequent to exposure. Rats exposed to 1 ppm S02 for 5 days, 60 ppm CO for 2 hours, 0.5 ppm N02 for 2 hours, or 0.25 ppm 03 for 2 hours showed no change while there was gastric inhibition at 300 ppm S02 for 2 hours, 1400 ppm CO for 1 hour, 26 ppm N02 for 2 hours and 1.5 ppm 03 for 2 hours. In most instances following chamber flushing recovery was complete within minutes. To evaluate the site and nature of stimulation, rats were also exposed to oil of mustard, benzaldehyde, hydrogen peroxide, amyl acetate, and “Old Spice” after sh ave lotion. Saturated dental paper points were introduced without obstruction into tracheal and retro-nasal cannulae. Oil of mustard but not benzaldehyde or amyl acetate inhibited gastric motility only when applied to the trachea. In general, the drop in activity was immediate and proportional to the degree of exposure. Nasal irritation was ineffective in eliciting the response. The experimental results lead to the following conclusions: 1) Toxic levels of these gases are associated with an inhibition of gastric motility that is not produced by .exposure of the nasal passages alone to the gases. 2) Toxic levels of these gases produced no demonstrable effect upon either total gastric acid secretion or total secretory volume. These findings tend to confirm earlier observations of an association between exposure to toxic concentrations of S02 and loss of gastric tone in the rodent stomach. |
