DESIRE FOR MUNCHIES ALL IN THE HEAD SAY SCIENTISTS

Even People Who Don't Smoke Dope Get The Munchies.

Cannabis-like molecules circulating in the brain, that occur naturally
in the body of even the most upright citizen, spark hunger pangs and may
contribute to obesity, says New Scientist magazine.

Known as cannabis receptors or cannabinoids, they could be the missing
link in solving the puzzle of why some people eat more than others.

Dr George Kunos and a team of researchers at Virginia Commonwealth
University in Richmond, Virginia, found the absence of cannabis
receptors in the brain made mice much less hungry.

It has been known for some time that a hormone called leptin tones down
hunger, but the reasons leptin works remain a puzzle.

Dr Kunos found that injecting leptin into rats and mice automatically
led to a sharp drop in cannabinoid levels.

Normally, mice that have been starved eat voraciously when finally given
something to eat.

Dr Kunos found that the absence of cannabis receptors changed their
habits.

Genetically modified mice lacking the receptors ate far less food than
usual after being starved for 18 hours.

Unmodified mice, given drugs to block the cannabis receptors, also ate
much less.

In a finding that could link cannabinoids to human obesity, Dr Kunos and
his team also found high levels of cannabis-like substances in the
brains of excessively fat mice. The mice were born with a genetic defect
that prevented them from making leptin.

Leptin's role as an appetite "off-switch" has been known since the
1990s.

Cannabinoids could be the missing part of the puzzle.

So, could too much natural cannabinoid - as opposed to the inhaled kind
- - in the brain make people fat?

"It's reasonable to speculate that it contributes to some forms of
obesity," Dr Kunos said.

The research backs up work by scientists at the Hebrew University in
Israel, who found that injecting newborn mice with drugs that
neutralised the effects of cannabis dramatically suppressed their
appetite - so much so that they stopped suckling and died.

In France, scientists are giving obese people an experimental drug
designed to block cannabinoid receptors.

In a trial lasting 16 weeks, a compound was given to patients to see if
it curbed their hunger.

Early results indicated the patients given the compound lost more weight
than the control group.