There might be hope on the horizon for people trying to counter the dizzying effects of too much alcohol over the festive season: some scientists say all you need do is watch your potassium channels.

Ethanol might be one of the most commonly used drugs, but scientists still have very little idea about how it causes the familiar signs of drunkenness - lack of coordination and loss of social inhibition.

Steven McIntire, a neurologist at the University of California in San Francisco, describes alcohol as "primarily a neuro-depressant drug", leading to sedation and coma. But he and his colleagues have identified a biological pathway which they believe is chiefly responsible for those feelings of sluggishness when tipsy.

Dr McIntire studied Caenorhabditis elegans worms which carried mutations on a gene encoding for the protein slo-1. This protein controls a "gateway" that allows potassium ions to move out of nerve and muscle cells. "The normal role of the channel is to dampen neural activity," Dr McIntire said. If the channel is activated inappropriately it can lead to those feelings of sluggishness.

Worms with mutations that made the potassium channel go into overdrive always acted as if drunk; worms with mutations that nearly stopped the potassium ions flow showed few signs of being drunk.

Variations in the slo-1 protein may explain why some people are less susceptible to the effects of alcohol than others.