Nicotine study opens path for anti-smoking drug

[zorba1]

by Marlowe Hood Marlowe Hood
PARIS (AFP) – Scientists have pinpointed a source of nicotine craving in the brain, opening up a new path towards drug treatments to help smokers kick their habit, according to a study released Sunday.
tobacco kills more than five million people every year and accounts for nearly one-in-10 adult deaths, 90 percent of them due to
In experiments with mice and rats, the researchers mapped the functioning of a gene called CHRNA5 that has been previously fingered in nicotine addiction.
The gene controls a receptor -- an entry point on the surface of brain cells -- which responds to nicotine molecules.
With a normal version of this gene, anything more than a tiny dose of nicotine triggers a message to the brain which says, in effect, "stop consuming," the scientists found.
Larger doses unleash a sense of repulsion, similar to "bad-tasting food or drink," lead researcher Paul Kenny at the Scripps Research Institute in Florida said in an email exchange.
But the effect was quite different in mice in which a tiny sub-unit of the receptor, known as alpha5, had been knocked out.
The negative message was never sent -- and as a result, the rodents couldn't get enough of the potent drug.
A similar scenario occurs naturally in some humans, the researchers believe.
Genome-wide screening studies have identified genetic alterations which impair the alpha5 unit's functioning.
Between 30 and 35 percent of the population in the [COLOR=#366388 !important][COLOR=#366388 !important]United [COLOR=#366388 !important]States[/COLOR][/COLOR][/COLOR] is thought to have a form of the CHRNA5 gene that encourages unbridled nicotine craving.
"Our data probably explain the fact that individuals with this genetic variation have increased vulnerability to developing [COLOR=#366388 !important][COLOR=#366388 !important]tobacco [COLOR=#366388 !important]addiction[/COLOR][/COLOR][/COLOR]," Kenny said.
"They are likely to be far less sensitive to the averse properties of the drug, and are thus more likely to acquire a nicotine habit."
On the strength of the new findings, published online in the journal Nature, Kenny has received funding from the [COLOR=#366388 !important][COLOR=#366388 !important]National [COLOR=#366388 !important]Institute [/COLOR][COLOR=#366388 !important]of [/COLOR][COLOR=#366388 !important]Drug [/COLOR][COLOR=#366388 !important]Abuse[/COLOR][/COLOR][/COLOR] to design a new category of drugs.
"This study has important implications for new approaches to tobacco cessation," said Jon Lindstrom, a neuroscientist at the University of Pennsylvania who has investigated other nicotine receptors in the brain and will participate in the follow-up research.
A truly effective anti-smoking drug may require targeting more than one receptor, he said.
"Nicotine influences complex brain circuits involved in reward" -- mainly through the release of dopamine -- "and memory," Lindstrom explained.

"It has beneficial effects on anxiety and attention, among other things, thus making quitting very difficult. [COLOR=#366388 !important][COLOR=#366388 !important]Withdrawal [COLOR=#366388 !important]symptoms[/COLOR][/COLOR][/COLOR] from quitting smoking make this worse."
Nicotine treatments, such as "patches", boost these reward circuits but can themselves be addictive.
Another widely-used drug reduces the craving and pleasure associated with cigarettes by partially blocking these other receptors. "Restoring or increasing the aversion to high doses of nicotine may complement these approaches and increase their efficacy, or replace them," Lindstrom said.Nicotine study opens path for anti-smoking drug - Yahoo! News

 

[kinabaloo]

Saw this on yahoo news where the key comes at the end :

With a normal version of this gene, anything more than a tiny dose of nicotine triggers a message to the brain which says, in effect, "stop consuming," the scientists found.

Larger doses unleash a sense of repulsion, similar to "bad-tasting food or drink," lead researcher Paul Kenny at the Scripps Research Institute in Florida said in an email exchange.

But the effect was quite different in mice in which a tiny sub-unit of the receptor, known as alpha5, had been knocked out.

The negative message was never sent -- and as a result, the rodents couldn't get enough of the potent drug.

A similar scenario occurs naturally in some humans, the researchers believe.

Genome-wide screening studies have identified genetic alterations which impair the alpha5 unit's functioning.

Between 30 and 35 percent of the population in the United States is thought to have a form of the CHRNA5 gene that encourages unbridled nicotine craving.​

Notice the leaps of faith. And the fact that 'impaired' is not the same as knocked out.

Key bit of the story :

On the strength of the new findings, published online in the journal Nature, Kenny has received funding from the National Institute of Drug Abuse to design a new category of drugs.​

Money. Revolving door. Drug pushers. Reducing complex begaviour to merely bio-chemical and then simplify again that complex system to a single receptor subtype that is said key to "nicotne addiction".

I'm not saying that the variation in this receptor subtype does not exist, but that it is not the holy grail claimed, just a little detail in a big picture. When examined more closely than first sight, it is just a theory.

Another researcher who commented on the findings (but who wlll now join the drug money bandwagon) at least said this :

"This study has important implications for new approaches to tobacco cessation," said Jon Lindstrom, a neuroscientist at the University of Pennsylvania who has investigated other nicotine receptors in the brain and will participate in the follow-up research.

A truly effective anti-smoking drug may require targeting more than one receptor, he said.

"Nicotine influences complex brain circuits involved in reward" -- mainly through the release of dopamine -- "and memory," Lindstrom explained.

"It has beneficial effects on anxiety and attention, among other things, thus making quitting very difficult. Withdrawal symptoms from quitting smoking make this worse."​

People smoke because they get help with anxiety and / or improved attention.

Ultimately though, what makes me mad when I see such reports is not the science tidbits but the misconceptions - that there is a need to cure 'nicotine addiction' (probably not true anyway that nicotine by itself is addictive) when what we really need to do is offer effective alternatives to tobacco combustion.