Breathing in fumes from gasoline made lab rats more aggressive, a finding that has wide implications for urban pollution, according to a study published on Tuesday.

Cairo University researcher Amal Kinawy exposed three groups of rats to either clean air, vapor from leaded gasoline, or vapor from unleaded gas.

Dissection of the rats showed that those exposed to gasoline had big fluctuations in a key group of neurotransmitters — chemicals used for exchanging messages between neurons — in three areas of the brain.

In addition, rats exposed to unleaded gas showed indications of neurological change. Their brain cells looked like rogue molecules called free radicals had damaged them.

Just as striking was that the rats exposed to either kind of fuel were more aggressive, spending more time in belligerent postures and carrying out more attacks, compared to the clean-air group.

Kinawy speculated that people chronically exposed to urban air polluted by traffic emissions may also be at risk of heightened aggression, although further research is needed to confirm this parallel.

"Millions of people every day are exposed to gasoline fumes while refueling their cars," she said.

"Exposure can also come from exhaust fumes and, particularly in the developing world, deliberate gasoline sniffing is a means of getting high."

Her study appears online in BMC Physiology, an open-access peer-reviewed journal published by the British-based BioMed Central.

Copyright AFP