Excessive sugar intake alters binding to dopamine and mu-opioid receptors in the brain

Palatable food stimulates neural systems implicated in drug dependence; thu s sugar might have effects like a drug of abuse. Rats were given 25% glucos e solution with chow for 12h followed by 12h of food deprivation each day. They doubled their glucose intake in 10 days and developed a pattern-of exc essive intake in the first hour of daily access. After 30 days, receptor bi nding was compared to chow-fed controls. Dopamine D-1 receptor binding incr eased significantly in the accumbens core and shell. In contrast, D-2 bindi ng decreased in the dorsal striatum. Binding to dopamine transporter increa sed in the midbrain. Opioid mu-1 receptor binding increased significantly i n the cingulate cortex, hippocampus, locus coeruleus and accumbens shell. T hus, intermittent, excessive sugar intake sensitized D-1 and mu-1 receptors much like some drugs of abuse. (C) 2001 Lippincott Williams & Wilkins.