Some new findings on Nicotine Addiction

nonicfrank
Joined: 07 Jan 2009, 19:23

17 Feb 2004, 09:12 #41

I had a couple quits before this one and noticed that i drank less alcohol when I was quit did anyone notice that. I think it had to do with the fact that I felt more depressed when i smoked.
just another benefit of not smoking that i will continue to do as long as I NEVER TAKE ANOTHER PUFF.
Reply

Joel
Joined: 18 Dec 2008, 23:57

28 Mar 2004, 06:33 #42

I see we have a few new members who are not only ex-smokers but also in recovery from alcoholism. I thought they would appreciate the information provided in this article.
Reply

John (Gold)
Joined: 18 Dec 2008, 23:57

30 Oct 2004, 21:41 #43

Image
The above Canadian government nicotine addiction warning label left many wondering if Canada wasn't overstating the power of this amazing chemical. As shown below the research neurochemical links between nicotine and heroin continue to grow more interesting. Still only one rule ... no nicotine just one day at a time ... NTAP! John (gold x5)
U-M team reports first evidence that smoking
affects brain's natural "feel good" chemical system
October 26, 2004 - University of Michigan Health System
Brain scan study suggests nicotine alters smokers' brain chemistry in ways that could help explain craving and satisfaction



SAN DIEGO - Smokers often say that lighting up a cigarette can calm their nerves, satisfy their craving and help them relax.
Image
A map of the brain showing the concentration of receptors for the brain's own "feel good" chemicals, called endogenous opioids. The red, orange and yellow areas have the highest concentrations of receptors, and therefore the most activity of opioid chemicals. In the U-M study, smoking caused major changes in the activity of the opioid system in several of these areas.
Now, a team of University of Michigan scientists is reporting new evidence of why that might be: Smoking produces major changes in the flow of "feel good" chemicals between brain cells, both temporarily and long-term. And those changes in flow match up with changes in how smokers say they feel before and after smoking.

It's the first time smoking has been shown to affect the human brain's natural system of chemicals called endogenous opioids, which are known to play a role in quelling painful sensations, heightening positive emotions, and creating a sense of reward. It's the same system that is stimulated by heroin and morphine.

The research team, from the U-M Medical School, will present the results Tuesday afternoon in a lecture at the annual meeting of the Society for Neuroscience.

The new results come from a pilot study involving a small group of young male pack-a-day smokers and non-smoking comparison subjects. Despite their study's small size, the researchers say the surprisingly large effect on opioid levels they found suggests a promising road for further discovery. That may lead to better understanding of why smoking affects people the way it does - including the mystery of why it's often so hard to quit, despite tobacco's many health dangers.

"It appears that smokers have an altered opioid flow all the time, when compared with non-smokers, and that smoking a cigarette further alters that flow by 20 to 30 percent in regions of the brain important to emotions and craving," says David J. Scott, a graduate student in the U-M Neuroscience Program who will present the results. "This change in flow as seen on a brain scan correlated with changes in how the smokers themselves reported feeling before and after smoking."
Image
The smokers in the study first smoked two special cigarettes that had almost no nicotine, then two regular cigarettes. All the while, they had their brains scanned and were asked to rate how they felt using a rating called the VAS scale. This graph shows that as the smokers switched to regular cigarettes, they felt less alert, anxious and craving, and more relaxed. This matched the changes in their brain chemistry.
Scott and his colleagues made the findings using a type of brain scanning called positron emission tomography, or PET, imaging. This allowed them to literally see activity in the endogenous opioid system when the study participants first smoked a special cigarette with almost no nicotine, and then smoked a regular cigarette. Before, during and after the scans, the participants rated how relaxed, alert, sick and nervous they felt, and how much they were craving tobacco.

The new findings confirm previous animal studies, and add to scientists' previous understanding of how smoking affects the flow of another "feel good" chemical in the brain, called dopamine. Now, the team is studying the interaction of dopamine and opioids in the brains of smokers and non-smokers.

They also hope to look at underlying genetic differences that might explain variations between people in response to nicotine - and perhaps differences in how easily people become addicted to cigarettes or quit smoking.

"The interaction of tobacco, and especially nicotine, with brain chemistry is a fascinating area that we're just beginning to understand, especially when it comes to correlating neurochemistry with behavior," says study leader Jon-Kar Zubieta, M.D., Ph.D., a U-M psychiatrist and neuroscientist. "Just as with the 'hard' drugs of abuse, such as heroin and cocaine, the phenomena of pleasure, addiction, increased tolerance and craving from tobacco are firmly rooted in neurochemistry."

Adds veteran tobacco researcher and U-M emeritus pharmacology professor Ed Domino, Ph.D., "Nicotine addiction is one of the most destructive forces in human health, and we must increase our comprehension of it in order to defeat it. This study represents a key step toward that goal."

Zubieta's team has spent several years developing and testing a way of using PET imaging to study the endogenous opioid system, and specifically the chemicals called endorphins and enkephalins.

Those are the same chemicals involved in the "runner's high", a pleasurable sensation brought on by strenuous exercise. But they're also important to blocking the flow of painful signals in the brain, and the U-M team has used the PET method to study how opioid levels change in response to pain, and how that response is affected by variations in hormone levels and genetic makeup.

The U-M team's PET scan method doesn't show the flow of opioids directly, but rather the status of tiny receptors on the surface of brain cells. These receptors, called mu-opioid receptors, act like locks that can only be opened when opioid molecules - either made by the brain or introduced from outside - bind to them. Morphine, heroin and some anesthetics produce their respective effects by binding to these receptors, and the drug-overdose treatment called Narcan blocks them.

The lower the level of natural opioids around, the more receptors there are available to other opioids - such as a special molecule developed by the U-M team. It's made of a short-lived radioactive carbon atom attached to a molecule of carfentanil, a morphine-like drug known to bind only to mu-opioid receptors. Using the PET scanner, the team can detect how much carfentanil is binding, and by extension how much natural opioid is flowing in that area.

In order to study the effect of nicotine on the opioid system, the team had to find a way to perform their study in the U-M PET scanner despite the strict no-smoking policy of the U-M's Hospitals and Health Centers. They also had to simulate every aspect of smoking except the nicotine, in order to control for all the other chemicals in tobacco smoke and sensory aspects of cigarette smoking.

So, they rigged up a system that allowed a person to smoke a cigarette while lying in the PET scanner having his or her brain scanned, and collected the smoke to vent it to the outdoors. They obtained special cigarettes from the Phillip Morris Research Center in Richmond, VA that had been treated to remove nearly all the nicotine. And they recruited six male smokers in their 20s who reported smoking more than 14 cigarettes each day.

They asked the participants to refrain from smoking for at least 12 hours before coming in for their scans, and tested their breath to make sure they hadn't cheated. The researchers injected the participants with the radioactive tracer form of carfentanil, and started the 90-minute PET scan. Then, they asked participants to rate their feelings on a sliding scale before lighting up a series of two de-nicotinized cigarettes, again between cigarettes, and again after two normal cigarettes.

At baseline, the smokers shower lower receptor levels before smoking. "This may suggest that continued exposure to nicotine had increased the neurotransmitter levels, that are being released under baseline conditions, for example after overnight abstinence from smoking," says Scott. "We are specifically examining this possibility in ongoing studies."

During the smoking of the de-nicotinized cigarettes, the smokers' brains started to show changes in opioid flow. But after they took a 20-minute break from smoking and then smoked regular cigarettes containing nicotine, the opioid levels changed dramatically.
Image Image
The orange dots on these brain scans show the areas where the biggest changes in opioid activity took place after smokers began smoking a regular cigarette. On the left is the cingulate, where activity increased 20 percent. On the right is the amygdala, where activity decreased by more than 20 percent.
In the area of the brain called the anterior cingulate, which is involved in emotion and emotion-memory integration, the activity of the opioid system increased by about 20 percent. This meant that far more endorphins and enkephalins were being released during smoking.

But the reverse was true in other key parts of the brain involved in memory, emotion and pleasure: the amygdala, the thalamus and the nucleus accumbens. In all three areas, the opioid system was 20 to 30 percent less active after the nicotine from the cigarettes was introduced.

This sharp drop in activity, most significantly in the amygdala and the thalamus, correlated with simultaneous reports from the smokers about how they were feeling after they smoked the normal cigarettes. As the opioid activity in their amygdala and thalamus decreased, they reported feeling more relaxed, less alert and nervous, and less craving than before.

Since smoking stimulates the release of dopamine in some of the same areas of the brain, Zubieta and his colleagues speculate that the connection between the opioid system and the dopamine system may be an important one to study.

As the research goes forward, the team will be analyzing brain scans, self-reported ratings and genetic samples from more smokers and non-smokers, to give them a better picture of the interaction between nicotine, the opioid system, behavior and inherited traits.

But for the moment, simply having shown that nicotine has an impact on the crucial "feel good" system is reward enough.

The research was funded by the National Institute on Drug Abuse, part of the National Institutes of Health. In addition to Scott, Zubieta and Domino, the research team included Lisong Ni, Ph.D., a research associate in Pharmacology, and Mary Heitzeg, Ph.D., a research fellow in the Department of Psychiatry and U-M Addiction Research Center. Zubieta is a member of the U-M Mental Health Research Institute, and a director of the U-M Depression Center.


U-M reseachers have also studied how the brain's opioid system responds to pain, and how differences in hormone levels and genes may help explain why some people can tolerate more pain than others. For more on this research, see press release Can't stand the pain? Your genes may be to blame or Pain and the brain.

For more information on how the U-M team developed and first tested their approach for making brain scan images that reveal the activity of the opioid system, click here.


Contact: Kara Gavin
(c) copyright 2004 Regents of the University of Michigan

Story Source:
Special Thanks to Sten for bringing this story to our attention!
Last edited by John (Gold) on 10 Jul 2009, 16:54, edited 1 time in total.
Reply

Joel
Joined: 18 Dec 2008, 23:57

12 Nov 2004, 01:59 #44

A new member just put up the following article. Being that we have the article discussed in this thread I am combining the two pieces. Although we caution all of our members to clear any articles with management before posting at the board.

Nicotine extends duration of pleasant effects of dopamine
By John Easton
Medical Center Public Affiars[/size]
Image
Brief exposure to low levels of nicotine not only boosts the brain's 'reward' system but also blocks a rival system that limits the duration of such rewards, report University researchers in the March 14 issue of the journal Neuron. The finding helps scientists understand why nicotine addiction takes root so quickly and lasts so long.

In 2000, a team from the same laboratory demonstrated how the first exposure to nicotine can create an enduring 'memory trace,' which instills the desire to repeat the experience and amplifies the pleasing effects of subsequent nicotine exposure. The current paper reveals how nicotine prolongs the reward period by disabling the system that counterbalances the drug's pleasant effects.

The reinforcing effect of nicotine is the primary reason people cannot quit smoking, despite widespread awareness that smoking causes cancer, heart disease, stroke, emphysema, bronchitis, vascular disease, cataracts and impotence. The World Health Organization attributes four million deaths each year to tobacco use.

"It would be difficult to design a better drug to promote addiction to this horrible habit," said neurobiologist Daniel McGehee, Assistant Professor in Anesthesia & Critical Care and director of the study. "It takes only a few exposures to create a lasting memory of the rewards of smoking, which are reinforced by each cigarette smoked. Now we find that nicotine also suppresses the brain's efforts to limit that pleasure."

The brain reward areas serve to acknowledge and reinforce beneficial behaviors, for example, eating when hungry. Specialized nerve cells encourage the body to repeat pleasing behaviors by releasing dopamine, the neurotransmitter associated with pleasant feelings, into these reward areas. "That was good," is the basic message of increased dopamine levels. "Do it again."

Unfortunately, drugs of abuse such as nicotine can usurp those pathways, providing the same sort of encouragement for harmful actions such as smoking.

McGehee and his colleagues, postdoctoral researchers Huibert Mansvelder and Russel Keith, working with brain tissue from rats, demonstrated how nicotine extends the duration of these rewards.

In previous work, McGehee's team showed that nicotine produces pleasure by attaching to the nicotinic acetylcholine receptor found on certain nerve cells. In response to nicotine, these nerve cells release a chemical signal called glutamate, which tells connected neurons to release dopamine. The more these nerve cells are excited, the more dopamine is released and the more pleasant the feeling.

In this paper, the researchers looked at the effects of nicotine on nerve cells that use a different chemical, called GABA, which inhibits dopamine release. These nerve cells have a slightly different version of the nicotinic acetylcholine receptor. Although they respond to the initial nicotine exposure, these receptors quickly become overwhelmed and lose their power to generate repeated releases of GABA. This renders them unable to reign in the excitation caused by nicotine. They remain disabled for up to an hour.

"As a result," said McGehee, "the reward system is turned on right away and it keeps sending reward signals for 60 minutes even though nicotine levels drop off 15 minutes after smoking. We suspect that this ability to extend the reward only enhances the drug's ability to reinforce smoking."

It may also provide a new target for drugs designed to help people stop smoking by interfering with nicotine's effects.


Original publication at http://chronicle.uchicago.edu/020328/nicotine.shtml
Reply

ZZRSteve GOLD
Joined: 19 Dec 2008, 00:01

02 May 2005, 21:17 #45

Image
I just counted and this post has been up 13 times since I quit but I'm only now getting around to really reading it Image. It's a great eyeopener and a great companion piece to John's Nicotine Addiction 101 . I highly recommend all us addicts to read it and all the responses as well. Steve, striving towards a nicotine free normal for 11 plus months now.
Last edited by ZZRSteve GOLD on 10 Jul 2009, 16:57, edited 1 time in total.
Reply

Joel
Joined: 18 Dec 2008, 23:57

13 May 2005, 17:57 #46

I think Steve was looking for this one. It is indexed under News and Sites. I put it there because it was a news article when first released.
Reply

ZZRSteve GOLD
Joined: 19 Dec 2008, 00:01

01 Jul 2005, 08:43 #47

"It would be difficult to design a better drug to promote addiction to this horrible habit," said neurobiologist Daniel McGehee, Assistant Professor in Anesthesia & Critical Care and director of the study. "It takes only a few exposures to create a lasting memory of the rewards of smoking, which are reinforced by each cigarette smoked. Now we find that nicotine also suppresses the brain's efforts to limit that pleasure." lifted from the above post
"The cost of such chronic pleasure is the minimizing of real life. That is what the real toll of smoking is--and the real benefit of quitting. Once again you can feel good from accomplishments. I think that is why people take greater pride in things after they quit". ......From Joel's response above
Newbies, oldbies, if you haven't delved into this post and Nicotine Addiction 101 I'd strongly urge you to. No wonder it's so hard to quit. No wonder we should be so proud of ourselves for doing it. We rule!!! Steve, adjusting my mind for 1 year and 47 days now.
"You gotta get your mind right Luke."
"Yessir boss. I'll never take another puff!"
Last edited by ZZRSteve GOLD on 10 Jul 2009, 16:55, edited 1 time in total.
Reply

Joanne Gold
Joined: 18 Dec 2008, 23:58

08 Mar 2006, 22:29 #48

A very interesting thread! I was able to share this information over the phone with a new quitter looking for counseling. Be sure to read Joel's latest additions.Image
Reply

Sharry
Joined: 18 Dec 2008, 23:57

07 Feb 2007, 04:13 #49

I am bumping this because it is pure fact and I, for one, can relate to it 100%.

Sharry

I have been quit for 2 Months, 2 Days, 13 hours, 18 minutes and 51 seconds (64 days). I have saved £193.66 by not smoking 968 cigarettes. I have saved 3 Days, 8 hours and 40 minutes of my life. My Quit Date: 04/12/2006 07:54
Reply

RJW118
Joined: 18 Dec 2008, 23:57

12 Oct 2007, 05:34 #50

I would be interested to know if there have ever been any studies on the effect on nicotine on the child brain vs the adolesent vs the adult brain.

As I recall the first cig I tasted at about 9 or 10 years old gave me the tremendous rush ...instant addict...

I have lived the largest part of my life under the impression that the normal me was in fact the me under the effect of the nicotine.

Being clean and free is a new experience in being me....I like it, but don't remember what I was like before the nicotine took over.
Reply