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Thursday, August 11, 2011

Scientists find genes linked to migraines

Posted: 14 June 2011

Migraine headaches
PARIS - Scientists have uncovered a trio of genes tied to migraine headaches, including one in which the link is exclusive to women, according to a study published on Sunday.

Migraines are acutely debilitating headaches - sometimes with an "aura", in which patients have the impression of seeing through frosted glass - that strike up to 20 percent of the population.

Scientists describe the condition, which is three to four times more common in women, as a brain disorder in which neurons, or brain cells, respond abnormally to stimuli.

The precise cause is unknown, but inheritance is thought to play a significant role.

To assess the genetic component, Markus Schuerks of Brigham and Women's Hospital in Boston coordinated an international sweep of genomes in 23,230 women, 5,122 of whom suffered from migraines.

So-called genome-wide association studies compare differences between individuals across the approximately three billion pairs of basic molecular building blocks found in the human genetic code.

The study, published on Sunday in the British journal Nature Genetics, is the largest to date of its kind. It found variations in three genes that showed up more frequently in migraine patients.

Two of them, known as PRDM16 and TRPM8, were specific to migraines, as opposed to other kinds of headaches.

TRPM8, in addition, was linked to migraines only in women. Earlier studies have shown that the same gene contains the genetic "blueprint" for a pain sensor, in both men and women.

The third suspect gene, LRP1, is involved in sensing the external world and in chemical pathways inside the brain.

"The brain of a person with migraine responds differently to certain stimuli, their nerve cells 'talk' differently to each other," explained Shuerks in an email.

"Many neurotransmitters are involved in this cross-talk and some seem to have a special role in migraines. LRP1 interacts with some of these neurotransmitter pathways and may thus modulate nerve responses that promote or suppress migraine attacks."

None of the genetic variants appeared to be connected specifically to migraines with or without auras.

The findings, published in Nature Genetics, were replicated in two smaller population-based studies, one in the Netherlands and the other in Germany, and in a clinical group followed by the International Headache Genetics Consortium.

"Inheritance of any of the genetic variants alters migraine risk by about 10 to 15 percent," said Schuerks.

The influence of these genes is probably not large enough to be immediately used as a diagnostic tool. But the result "is an advancement of the understanding of migraine biology," he said.

- AFP/al


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Scientists find genes linked to migraines

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Smokers are thinner than those who don't smoke

So is this really the key to controlling obesity? And would you take this 'medicine'?

Posted: 10 June 2011

WASHINGTON: US scientists have figured out exactly how nicotine acts as an appetite suppressant in the brain, a finding that could one day help in the fight against obesity, researchers said on Thursday.

Smokers tend to be thinner than people who don't smoke, and the study led by Yale University and published in the journal Science describes how nicotine activates certain neurons in a part of the brain called the hypothalamus.

Those neurons tell the body when it's had enough to eat, according to senior author Marina Picciotto, a professor of neurobiology and pharmacology at Yale.

"Many people say they won't quit smoking because they'll gain weight. Ultimately, we would like to help people maintain their body weight when they kick the habit and perhaps help non-smokers who are struggling with obesity."

Researchers made the discovery by studying mice, but are hopeful that similar receptors can be isolated in humans, too.

A research scientist in Picciotto's lab was studying nicotinic acetylcholine receptors, which are on the surface of neurons, to see if an experimental drug to treat depression would have any effect.

"He noticed that mice given the drug ate less than those not on the medication," said the study, which led to a wider investigation with researchers at Carleton University in Ottawa, Canada and the University of Hawaii.

A series of experiments showed that the drug could turn on a certain nicotine receptor which then told a subset of neurons in the hypothalamus - called pro-opiomelanocortin or POMC cells - that dinner time was over.

The receptor was also independent of the ones that trigger the craving for nicotine in smokers.

"This suggests it is possible to get the effect of appetite suppression without also triggering the brain's reward centres," Picciotto said.

"Identifying this receptor is important for the understanding of the mechanisms related to addiction, weight and smoking."

- AFP/de


Taken from; source article is below:
Smokers are thinner than those who don't smoke

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