Amiloride increases sodium chloride taste detection threshold in rats

The epithelial sodium-channel blocker amiloride has been shown to inhibit sodium responses in the 7th cranial nerve of the rat. In the signal detection task used in this study, amiloride (100 mu M) treatment raised the NaCl threshold by similar to 1 log(10) unit. The inhibition constant for amiloride was 1 mu M at 0.013 M NaCl. Because the NaCl intake of adult rats has been shown to be related to the level of dietary NaCl exposure early in development, rats were exposed by way of maternal diet to 1 of 3 diets (0.1% NaCl, n = 8; 1.0% NaCl, n = 8; 3.0% NaCl, n = 9) from conception through weaning, to determine whether this treatment affects taste sensitivity. At Postnatal Day 30, rats were placed on 1.0% NaCl chow. This treatment did not affect NaCl detection or amiloride sensitivity id adulthood. The amiloride-induced shifts in NaCl sensitivity functions imply that the transcellular sodium transduction pathway is necessary for normal NaCl detection in the rat.