Enhancement of the perceived sucrose sweetness in the rat by thaumatin

After conditioned aversion to a 0.18 mol/l sucrose solutionrats do not reject a solution of 0.03 mol sucrose per l (nearthreshold) or a solution of thaumatin (0.2 g/l), which elicitsno response in the rats' taste nerves. However, a mixture ofthe latter two solutions is rejected just as the 0.18 mol/lsucrose solution. This means that for the rat the mixture hasa sucrose-like taste. So, thaumatin enhances sucrose-like sweetnessin this animal. Electrophysiological measurements in the chordatympani indeed show an enhancement of the sucrose response ofalmost 20 percent by the addition of thaumatin (0.2 g/l) toa sucrose solution of 0.5 mol/l.