ECSTASY may hit the people who take it with a potentially fatal double
whammy鈥攏ot only generating too much heat but also blocking a crucial way
of cooling down.
Most research into the effects of ecstasy has focused on heat production. The
drug increases the metabolic rate, and people who take it often dance for hours.
Both of these factors generate extra heat.
鈥淭he most dangerous thing is that body temperature climbs so rapidly,鈥� says
Rod Irvine, a pharmacologist at the University of Adelaide. 鈥淭he membranes start
to break down, and you get renal failure. The brain swells and is basically
肠谤耻蝉丑别诲.鈥�
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The effects can be so extreme that William Blessing and his colleagues at the
Flinders Medical Centre in Adelaide wondered if the drug was also affecting the
body鈥檚 ability to cool itself. And sure enough, when they gave ecstasy to
rabbits they found that it triggered severe constriction of the blood vessels
leading to the skin in their ears. 鈥淏lood flow drops to near zero straight
away,鈥� says Blessing. 鈥淭he ear goes as white as a sheet.鈥�
Diverting blood to the skin is an important way of cooling down, so this
effect could contribute to the heatstroke that has killed over 100 people
worldwide since ecstasy hit the club scene 15 years ago.
A drug called clozapine restored blood flow in the rabbits鈥� ears to near
normal. Clozapine blocks serotonin receptors in the brain, and is normally used
to treat schizophrenia. It can have severe side effects, so it would not be
ideal as an antidote to ecstasy, but Blessing suggests that similar drugs could
help people suffering from heatstroke. 鈥淧harmaceuticals companies are developing
similar drugs without the side effects,鈥� says Irvine. 鈥淭hey could be useful for
treating ecstasy overdoses.鈥�
Blessing says it鈥檚 not surprising that ecstasy affects blood flow as well as
mood, since similar parts of the brain regulate both functions. For instance,
recent studies in his lab suggest that blood flow to the skin is controlled by
the amygdala, a region of the brain that also plays a key role in sexual
behaviour, emotions and aggression. The link may have evolved because animals
mating or fighting are more likely to get injured, says Blessing. Shutting down
blood flow to the skin would help reduce bleeding.
Blessing presented the findings at a conference on the cardiovascular system
in Sydney last week.