In addition to evoking behavioural responses, sweet taste stimuli can elicit preabsorptive cephalic phase responses, such as insulin release,[2-4] activate endogenous opioidergic, dopaminergic and serotonergic systems[5-12] and produce analgesic effects in children and young animals.[13-17] Taste responses to sweeteners are modulated by post-ingestive feedback and hormones.[18-24] Because ingested sugars evoke sweet taste sensation and also produce rewarding post-ingestive feedback,[25-27] sweet taste preferences can be modified by the experience of consuming sugar. These effects of experience are strong enough to alter initial genetic differences in sweet taste responsiveness.[28-30] Although appetitive responses to sweet taste stimuli are inborn in many animals,[31,32] they are also often modulated by environment and depend on genetic factors.[33,34] The interactive mechanisms of sweet taste suggest that it is a part of a complex ingestive behaviour and is likely to be determined by multiple genes.
