[lou_lou]

http://psychologytoday.com/articles/...000001&print=1

Since dopamine is also involved in learning, memory and motivation, the chemical helps us pay attention to the information we need to survive, act upon it, and remember it for the future. But drugs hijack that machinery, sending 5 to ten times as much dopamine surging through the nucleus accumbens and forcing the brain's motivational and attentional mechanisms to focus purely on the drug. It becomes the most interesting and important thing in the world. "In any addicted person, what's salient is the drug," says Volkow. "There's no competition."

Over time, the addict's brain adapts to the torrent of dopamine by dampening the system down. Imaging experiments show that cocaine addicts' brains don't react to the things that turn on the rest of us, whether that's romantic passion, food or cold, hard cash. Volkow's research has also shown that addicts have fewer dopamine D2 receptors, which are found in parts of the brain involved in motivation and reward behavior. With fewer receptors, the dopamine system is desensitized, and the now-understimulated addict needs more and more of the drug to feel anything at all. Meanwhile, pathways associated with other interesting stimuli are left idle and lose strength. The prefrontal cortex—the part of the brain associated with judgment and inhibitory control—also stops functioning normally. It's a neurological recipe for disaster. "You have enhanced motivation for the drug, and you have impaired prefrontal cortical systems. So you want the drugs pathologically, and you have reduced control of behavior, and what you've got is an addict," says University of Michigan, Ann Arbor psychology professor Terry Robinson, who pioneered this new way of thinking about dopamine with his University of Michigan colleague Kent Berridge.

Some people are apparently born with fewer dopamine receptors, and they are more likely to enjoy the rush of addictive drugs. In one imaging experiment, Volkow gave Ritalin, which gently lifts dopamine levels, to a group of ordinary volunteers. Some loved the feeling of the drug, but others hated it so much that they threatened to drop out of the study. Volkow was puzzled until she imaged their brains. She found that those who liked the rush from the drug had fewer dopamine D2 receptors than those who hated it. Volkow thinks that some people have a sensitive dopamine circuitry; they can't take the additional stimulation of drugs.

Obesity may involve similar malfunctions in the dopamine system. Volkow's longtime Brookhaven collaborator Gene-Jack Wang has discovered that the brains of seriously obese people seem to be tuned toward food. Even when they are lying quietly in the scanning machine, the sensory cortex of their mouth, tongue and lips is more active than it is in normal-weight people, he says: "They are putting out their antennae." Yet he also found that the dopamine circuitry of heavy people is less responsive, with fewer dopamine D2 receptors. Even among the obese, there are dopamine differences. The heaviest people in his study had fewer dopamine receptors than the lightest. Like addicts, overeaters may be compensating for a sluggish dopamine system by turning to the one thing that gets their neurons pumping.

It's a mark of changing times—and more sophisticated science—that the head of the National Institute on Drug Abuse is thinking about doughnuts as well as heroin. Just as blaming drug addiction on moral weakness was a shortsighted and unscientific way of framing a social problem, Volkow believes that focusing solely on metabolism, or blaming fat people for overindulgence and gluttony, are intellectual dead ends. "What motivates us to eat is clearly much more than hunger," she says. "We need to expand the way we think about eating." Wang and Volkow suggest that dopamine may provide a new window into weight loss: Animal studies have shown, for example, that exercise elevates dopamine release and increases dopamine D2 receptors.

Volkow and the other champions of the new view of dopamine don't deny that the chemical helps us register pleasure. But they think that pleasure is just part of a set of interconnected dopamine-related behaviors. Volkow recently found that adults with attention deficit disorder who took dopamine-boosting Ritalin before taking a math test found it easier to concentrate, in part, because the task seemed more interesting, so they felt more motivated to do the problem.

From this angle, it makes sense that the cognitive process of absorbing new information is closely tied to the brain's pleasure mechanisms. You might say that what the brain really "wants" is new information, suggests Gregory Berns, associate professor of psychiatry and behavioral sciences at Emory University in Atlanta. "Neurons really exist to process information. That's what neurons do. If you want to anthropomorphize neurons, you can say that they are happiest when they are processing information."

This urge to connect to the world and learn from it is more important than mere pleasure, says Volkow. It's part of the most basic force in behavior: the will to live. It's not automatic, she points out. Seriously ill or very depressed people can lose the will to survive. "What is the motivation we all have to be alive, to do things?" she asks. "It's not pleasure. Our lives would be so much simpler if we were motivated just for the sake of pleasure."

But dopamine sensitivity and addiction aren't genetically determined or inevitable. One experiment with monkeys showed that the dopamine system may be influenced by social interactions: Animals that lost social status also lost D2 receptors. Context is also crucial. Obviously, it's easier to get hooked if drugs are easy to get in your neighborhood, but it's not just a question of supply and demand. People who grow up in stimulating, engaging surroundings are protected against addiction, Volkow believes, even if they don't have a naturally responsive dopamine system. If you connect to the world in a meaningful way, and have more chances to get excited about natural stimuli, you're less likely to need an artificial boost.

"If you don't get excited by everyday things in life, if things look gray, and the drug makes things look extraordinary, that puts you at risk," she says. "But if you get great excitement out of a great multiplicity of things, and intensely enjoy these things—seeing a movie, or climbing a mountain—and then you try a drug, you'll think: What's the big deal?" For those lucky enough to grow up as Volkow did, surrounded by sharp minds and fascinating history, drugs are just nowhere near as interesting as everyday life.

[rosebud]

thanks for this. I believe that I am a dopamine addict. I get my adrenaline supply form dopamine. One of the things that I have just thought about over the last few months is that when you go to a Neuro, how often do they ask you what's happening in your life? Any divorce, did your house burn down recently...or not so recently. How are your kids doing? NO! I have never been asked by any neurologist and I have seen a passle of them (lots). I believe my problems began when I was put on anti depressants and high blood pressure medication 14 years ago when I was having a personal hurricane rip through my life. I think one human error, or imcompetant physician led to a series of dangerous combinations that caused me to receive a PD diagnosis and as the saying goes "it was all downhill from there"
It is human nature to be arrogant -especially if you are a "professional" in your field. The more passive types who know me say "oh she's in denial" but I do not believe I am. I have observed the patterns and struggled with the truly unusual for so long that I can see the path. I believe I know what is wrong with me and unfortunatley for me, no professional has done the research to confirm what I am experiencing and so its just all in my head. Worse yet, I don't think even if my beliefs were confirmed, they would have any idea how to fix it. I do have PD now because my body has had a free supply of dopamine courtesy of "the system" for the last 10+ years. I have drug induced PD. I do not believe that is true of everyone, but every neuro who sees me is baffled by my unusual manifestation of the disease. Exercise is the only thing that is keeping me with my head above water. I wonder how many have had DBS, or died because of what the medical wizards don't know. Too many I think. Well this has been quite a rant. I have to go take a few dozen pills now so I can continue to rant tomorrow! Not my usual cheery post and double

[lou_lou]

I am very ticked at the medical community for either being liars or
selling us drugs we will become addicted to, since they are giving our medicine to one teenager -I know her because I know her mom,
she told me very as a matter of fact -they give my daughter -your medicine
-and I said, why? does she have PD? she said -no for RLS, restless leg syndrome?
cs -picked up on this as well...
in the very beginning when I decided to take the meds at the advice
of a neuro from the midwest -after he told me - what are you waiting for?
I told him - I felt the drug called sinemet was addictive, he said, you are wrong! and he was the one that piledddd about 6 prescriptions on me -in a very small time period, before this I shook and was tired all the time, but not
completely on a high, I could not even cry...
I felt like I was in a dark cloud, I began to gamble?
this was not me... I told this to my friend who was a nurse, she said tell him you want off these drugs, I asked the doctor, and he asked me why I waned off of them? he said to me you cant live without these...
so I believed him.
I became for the most part insane - like my dear friend w/ PD -who killed herself -she was so young, and I will not say her name, but all who attended
the first 2000 DC gala w/ Mike Fox knows -about who I am speaking.
I realized I was not all there -but so many bad things were happening to me
at the time... and I can't hardly remember some things like my sons age or
where I was, how I got there,
I do not know why except for the grace of God - why I am not dead now?
I lived in my car, I went to live with a great lady and her husband who had PD
who just passed away this spring - they were part of what I needed, someone to care about me...
and it was then she took me off mirapex cold turkey... not a good idea -
but that was great but when I returned home -the doctor scolded me for not taking mirapex, what a vicious B-tard he was, they do not know anything about these drugs they are legally dispensing.
I am sorry, but I know from a great man who is a doctor -that we are for the most part addicted -these are happy drugs?
palliative - not cures, not even close...
that is why we have problems with ons and off's -

PS. another reason is because my life insurance policy was cancelled after finding out I had PD -I asked them why and the person
was a be-yotch she said -it is well documented PD patients have a high rate of "suicide"
I started crying and hung up the phone... I want to see this documentation! -

love -

[indigogo]

Tena - thanks for posting this article - I think it speaks the truth. Not only is sinemet to blame, but so are the agonists (that's why they are linked to increased obsessive compulsive behaviors). Our damaged dopamine systems is why depression is so prevalent among us.

We are all guinea pigs as PD patients - no one knows the exact nature of this beast we are dealing with; the knowledge expands on a daily basis; the treatment possibilities do not keep up. Sinemet is a sledge hammer.

The statistic I have heard about PD and suicide is that we think about it more, but follow through less.

[lou_lou]

dear carey,
I hope I did not upset you or rosebud, but we are being led down a drug addicts path?

Dopamine and Addiction


Imran Siddiqui
Dopamine is neurotransmitter in the brain that plays vital roles in a variety of different behaviors. The major behaviors dopamine affects are movement, cognition, pleasure, and motivation (1). Dopamine is an essential component of the basal ganglia motor loop, as well as the neurotransmitter responsible for controlling the exchange of information from one brain area to another (1). However, it is the role that dopamine plays in pleasure and motivation that attracts the most neurobiologists attention as well as mine.

In certain areas of the brain when dopamine is released it gives one the feeling of pleasure or satisfaction (1). These feelings of satisfaction become desired, and the person will grow a desire for the satisfaction. To satisfy that desire the person will repeat behaviors that cause the release of dopamine (2). For example food and sex release dopamine (2). That is why people want food even though their body does not need it and why people sometimes need sex. These two behaviors scientifically make sense since the body needs food to survive, and humans need to have sex to allow the race to survive. However, other, less natural behaviors have the same effect on one's dopamine levels, and at times can even be more powerful. Often these behaviors can result in addiction due their effect on dopamine, and that addiction can have negative effects on a person's well-being. Two of such behaviors are

http://serendip.brynmawr.edu/bb/neur...isiddiqui.html

DOPAMINE AND REWARD
http://arjournals.annualreviews.org/....020189.001203

[lou_lou]

http://tinyurl.com/ywmcak

Development of the Nervous System
By Dan Harvey Sanes, Thomas A. Reh, William A. Harris

Development of the Nervous System, Second Edition has been thoroughly revised and updated since the publication of the First Edition. It presents a broad outline of neural development principles as exemplified by key experiment...
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peace,
tenalouise



God comes to us in the brokenness of our health, in the shipwreck of our family lives, in the loss of all possible peace of mind, even in the very thick of our sins. He saves us in our disasters, not from them.
Robert Farrar Capon

[reverett123]

Explains the role of dopamine in addiction. Also explains the action of a drug to comat addiction called Sudoxon. One of the two components is naloxine (sp?) that some here are taking. Interesting.

[reverett123]

It's late, OK?

http://suboxoneassistedtreatment.org/19.html

[jcitron]

That's an interesting link. I've spent some time reading it. I think I've read a lot of this somewhere else. I took a college class called "Drug Dependency in The Workplace". We had to research the effects of drugs, and what they do to the brain and body.

John

[bluedahlia]

Now I know why I get that little signal in the pit of my stomach about half an hour before the levadopa wears off. My body is asking for more. Interesting.