Meth And Milkshakes - National Geographic

Meth support websites are littered with stories of addicts hankering for sweets but, as far as I can tell, the topic gets little attention in the scientific literature. (I did find one report, conducted by dentists, showing that meth users are more likely to drink soda than are non-users.) A fruit fly study published yesterday provides a possible molecular explanation for the meth-induced sweet tooth.

Most meth research has zeroed in on the brain. The drug spurs excessive release of dopamine, a brain chemical that activates reward pathways and leads to euphoria. Meth use also kills neurons — perhaps, some say, because of toxic chemicals that are released when all of that extra dopamine breaks down. (Because of this neurotoxic effect, meth-exposed mice can be used to model Parkinson’s disease.)

If you’ve ever seen a meth addict, though, you know that the drug wreaks havoc on many other parts of the body. It can damage the heart, lungs, liver, stomach, kidneys, skin, and even sperm. The scientists behind the new study wanted to get a better idea of how meth affects the entire body.

The researchers extracted genetic material from whole frozen flies whose food had been mixed with meth. Then they analyzed the expression patterns of many different genes. (Gene expression is how much RNA or protein is made from a particular gene.)  They found that, compared with normal flies, meth-exposed insects have abnormal expression of a host of genes. These genes are involved in (among other things) iron and calcium regulation, the birth of sperm, muscle contraction and — bingo — carbohydrate metabolism.

Following up on the carb finding, the researchers did a second experiment in which they fed flies both meth and trehalose, a common blood sugar in insects. These flies lived much longer (about 92 hours) compared with flies who ate meth without that extra sugar (50 hours).