Sweet and Sweetener Units

Having a "sweet tooth" might seem like a uniquely human characteristic, but it turns out that mice also show differences in their taste for sweets.

B6 and 129 mice differ in their allelic expression of TasIr3, which encodes a component of the sweetener-binding receptor. McCaughey used single-unit recording of neurons in the nucleus of the solitary tract (NST), where peripheral taste fibers converge. In each strain, NST cells responded preferentially to sucrose, salt, or acid (S-, N-, and H-cells, respectively). B6 mice had more S-cells, and all neurons responded more strongly to sucrose than did neurons of 129 mice. The author deduced that strain differences likely arose from a reduced binding efficiency between sweeteners and their T1R2/T1R3 receptors in 129 mice. In response to saccharin, the response patterns suggested that B6s perceived the artificial sweetener as sweeter and less salty than 129s.

By Society for Neuroscience