Antinociceptive effect of sucrose ingestion in the human.

Sucrose ingestion has been shown to alleviate pain and distress in rats, human infants as well as adults. Sucrose induced analgesia is related to the reward value associated with its sweet taste. The sweet taste of sucrose is a stimulus for the activation of endogenous opioid pool. The opioids in turn modulate pain perception. It has been demonstrated in a number of animal and human studies that sucrose ingestion increases the hypothalamic/CSF opioid levels. This gains support from the results obtained from naloxone challenge test, a neuro-endocrine method for assessment of endogenous opioid tone. Moreover, the analgesic effects of sucrose can be reversed by administration of opioid antagonists such as naloxone. On the other hand, long-term sucrose ingestion leads to hyperalgesia in rats and it has been hypothesized to result from a complex interaction of sucrose with the endogenous opioid system leading to a deficiency of opioids. In the present article mechanisms underlying sucrose induced analgesia including the interaction of the palatability and reward value of food with the neural substrates and its neuro-chemical basis have been reviewed in the light of both animal and human studies. In addition, clinical application of the knowledge about sucrose and its modulatory effect on the endogenous opioid system has been suggested.