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Dr. Bob is Robert Hsiung, MD,
bob@dr-bob.orgShown: posts 1 to 13 of 13. This is the beginning of the thread.
Posted by tina on June 9, 2003, at 18:22:40
Can anyone tell me if smoking cigarettes alters brain chemistry at all? I started smoking again a few days ago and my mood has vastly improved. I haven't felt this good in ages.
Does nicotine do anything to neurotransmitters?
thanks
tina
Posted by Paulie on June 9, 2003, at 18:50:12
In reply to Nicotine and brain chemicals, posted by tina on June 9, 2003, at 18:22:40
Nicotine appears to be an MAO-B inhibitor increasing DPA. This is the reasoning why Zyban,which blocks the re-uptake of DPA, can reduce the craving for nicotine.
SELEGILINE (l-deprenyl)
A recent New York study showed that smokers had on average 40% less of the enzyme, monoamine oxidase type-B, in their brains than non-smokers. Levels returned to normal on their giving up smoking. Not merely is the extra dopamine in the synapses rewarding. The level of MAO-b inhibition smokers enjoy apparently contributes to their reduced incidence of Parkinson's and Alzheimer's disease.It is much better though to take a DPA agonist than to smoke.
Paul
Posted by Larry Hoover on June 9, 2003, at 20:54:48
In reply to Nicotine and brain chemicals, posted by tina on June 9, 2003, at 18:22:40
> Can anyone tell me if smoking cigarettes alters brain chemistry at all? I started smoking again a few days ago and my mood has vastly improved. I haven't felt this good in ages.
> Does nicotine do anything to neurotransmitters?
> thanks
> tinaYup. Nicotine does lots of things in the brain.
Int J Clin Pharmacol Ther. 2002 Sep;40(9):404-18.
A review of the pharmacological and psychopharmacological aspects of smoking and smoking cessation in psychiatric patients.
Haustein KO, Haffner S, Woodcock BG.
Institute for Nicotine Research and Smoking Cessation, Erfurt, Germany. haustein@inr-online.de
The data reviewed confirm that mentally ill patients smoke twice as many cigarettes as patients without mental illness. The secretion of neurotransmitters such as noradrenaline, serotonin, dopamine, acetylcholine, gamma-amino-butyric acid and glutamate is increased by the binding of nicotine to central nicotine receptors. There are also data showing that serotonin formation and secretion in patients with mental illness are influenced by chronic smoking. Cigarette smoke inhibits the activity of monoamine oxidase B, which is responsible for the catabolism of several brain neurotransmitters. Patients suffering from major depression show a comorbidity between heavy smoking and the disease. In patients with schizophrenia treated with neuroleptics, increased cigarette smoking reduces adverse reactions to the drug therapy presumably because of an increase in metabolism of the neuroleptics. There is also evidence suggesting that quitting smoking is more difficult for mentally ill patients than patients without psychiatric disease. (abstract snipped)
Posted by zenclearer on June 9, 2003, at 21:59:04
In reply to Re: Nicotine and brain chemicals, posted by Paulie on June 9, 2003, at 18:50:12
But smoking has been correlated with reduced cognitive performance as one ages. Likely the vascular effects: reduced blood flow to brain.
> Nicotine appears to be an MAO-B inhibitor increasing DPA. This is the reasoning why Zyban,which blocks the re-uptake of DPA, can reduce the craving for nicotine.
>
> From http://biopsychiatry.com
>
> SELEGILINE (l-deprenyl)
> A recent New York study showed that smokers had on average 40% less of the enzyme, monoamine oxidase type-B, in their brains than non-smokers. Levels returned to normal on their giving up smoking. Not merely is the extra dopamine in the synapses rewarding. The level of MAO-b inhibition smokers enjoy apparently contributes to their reduced incidence of Parkinson's and Alzheimer's disease.
>
> It is much better though to take a DPA agonist than to smoke.
>
> Paul
Posted by tina on June 9, 2003, at 22:20:44
In reply to Re: Nicotine and brain chemicals, posted by zenclearer on June 9, 2003, at 21:59:04
I'm so stupid and thick when it comes to this kind of scientific language guys. Could you explain this stuff in laymans terms for me?
It's all greek right now......I'm not being funny, I'm really serious about not understanding the studies that you posted.
thanks for the help
tina
Posted by Larry Hoover on June 9, 2003, at 22:41:45
In reply to Re: Nicotine and brain chemicals--HELP, posted by tina on June 9, 2003, at 22:20:44
> I'm so stupid and thick when it comes to this kind of scientific language guys. Could you explain this stuff in laymans terms for me?
> It's all greek right now......
>
> I'm not being funny, I'm really serious about not understanding the studies that you posted.
>
> thanks for the help
> tinaThe abstract I posted provides evidence that nicotine enhances the release of a variety of neurotransmitters, some with exciting and some with calming effects. Most people experience just that sort of blend, sharper cognition, but a bit calmer or more mellow at the same time.
Nicotine also blocks the breakdown of some neurotransmitters by inhibiting the enzyme monoamine oxidase, the same thing that MAOI drugs like Parnate and Nardil do (though nicotine is much less able to do this the latter two drugs).
One theory about why nicotine causes addiction is that your brain becomes accustomed to the effects of nicotine, and adjusts the release of neurotransmitters downwards, to compensate for the stimulation from the nicotine. So, you smoke to feel normal, because without nicotine, you feel worse. Others argue that nicotine is addictive because it directly stimulates the "reward pathway", a dopamine-based group of linked neurons that give you a pleasurable sensation when they become activated. I think it's a little of both.
I hope this helps. If not, let me know.
Lar
Posted by Boba Fat on June 10, 2003, at 3:53:53
In reply to Re: Nicotine and brain chemicals--HELP » tina, posted by Larry Hoover on June 9, 2003, at 22:41:45
Interesting topic, I gave up properly smoking years ago but becaus I now smoke only very rarely the effects hit me more. I find smoking an occasional cigar can be very stress relieving and also heighten the kick I get from benzo's and codeine.
Posted by samplemethod on June 10, 2003, at 6:30:52
In reply to Re: Nicotine and brain chemicals, posted by Paulie on June 9, 2003, at 18:50:12
I would be interested in finding scientific evidence that nicotine is a MAO-B inhibitor. My impression was the cigarettes, or more correctly something within the cigarettes when smoked, actually affects MAO-B. It may well be nicotine, but I havent seen any proof of that yet.
Cheers> Nicotine appears to be an MAO-B inhibitor increasing DPA. This is the reasoning why Zyban,which blocks the re-uptake of DPA, can reduce the craving for nicotine.
>
> From http://biopsychiatry.com
>
> SELEGILINE (l-deprenyl)
> A recent New York study showed that smokers had on average 40% less of the enzyme, monoamine oxidase type-B, in their brains than non-smokers. Levels returned to normal on their giving up smoking. Not merely is the extra dopamine in the synapses rewarding. The level of MAO-b inhibition smokers enjoy apparently contributes to their reduced incidence of Parkinson's and Alzheimer's disease.
>
> It is much better though to take a DPA agonist than to smoke.
>
> Paul
Posted by Larry Hoover on June 10, 2003, at 6:51:46
In reply to Re: Nicotine and brain chemicals, posted by samplemethod on June 10, 2003, at 6:30:52
> I would be interested in finding scientific evidence that nicotine is a MAO-B inhibitor. My impression was the cigarettes, or more correctly something within the cigarettes when smoked, actually affects MAO-B. It may well be nicotine, but I havent seen any proof of that yet.
>
>
> CheersQuite right. I did a sloppy reading of the originally posted abstract, and had a similar incorrect statement. Nicotine isn't an MAOI, but cigarette smoke is (probably from cotinine). It comes as no surprise then, why nicotine replacement is an incomplete substitute for smoking.
Nicotine Tob Res. 2001 Nov;3(4):383-90.
Platelet monoamine oxidase, smoking cessation, and tobacco withdrawal symptoms.
Rose JE, Behm FM, Ramsey C, Ritchie JC Jr.
VA Medical Center, and Department of Psychiatry, Duke University Medical Center, Durham, North Carolina 27705, USA. jerose@acpub.duke.edu
Previous studies have found that constituents in tobacco inhibit both forms of the enzyme monoamine oxidase (MAO-A and MAO-B). This enzyme is important in the breakdown of the amine neurotransmitters, including dopamine, which is thought to mediate the reinforcing effects of nicotine and contribute to tobacco dependence. To further examine the relationship between cigarette smoking, smoking cessation and MAO, we measured platelet MAO-B activity in 16 smokers before and after being switched to smoking denicotinized cigarettes; in a subset of six subjects who subsequently quit-smoking, MAO-B activity was also measured at 1 and 4 weeks following cessation. Smoking cessation treatment was provided in an open-label format, and included nicotine skin patch treatment in conjunction with oral mecamylamine (a nicotinic antagonist) and neostigmine (a peripherally acting acetylcholinesterase inhibitor, administered to counteract constipation experienced from mecamylamine). Results showed that smoking behavior, indexed by expired air carbon monoxide levels, was negatively correlated with platelet MAO-B activity prior to smoking cessation. Moreover, MAO-B activity significantly increased by approximately 100% at 4 weeks after quitting smoking. However, little or no recovery occurred within the first week of abstinence, suggesting that the constituents in tobacco responsible for MAO inhibition may have half-lives of several days. Thus, if relapse to smoking is due in part to withdrawal from the MAO-inhibiting effects of tobacco, this effect likely occurs more than 1 week after quitting. Additionally, low baseline MAO-B activity significantly predicted the intensity of withdrawal symptoms reported upon switching to the denicotinized cigarettes as well as after smoking cessation. These results support the view that MAO inhibition from non-nicotine constituents in cigarette smoke is relevant to tobacco dependence and that continued investigation of the potential use of MAO inhibitors in smoking cessation treatment is warranted.
Int J Neuropsychopharmacol. 2001 Mar;4(1):33-42.
Monoamine oxidases and tobacco smoking.
Berlin I, Anthenelli RM.
Department of Pharmacology, Pitie-Salpetriere University Hospital, Paris, France. ivan.berlin@psl.ap-hop-paris.fr
Although nicotine has been identified as the main ingredient in tobacco responsible for aspects of the tobacco dependence syndrome, not all of the psychopharmacological effects of smoking can be explained by nicotine alone. Accumulating preclinical and clinical evidence has demonstrated that smoking also leads to potent inhibition of both types (A and B) of monoamine oxidase (MAO). Smokers have 30-40 % lower MAOB and 20-30 % lower MAOA activity than non-smokers. Reduced MAO activity in smokers has been shown by direct measures (platelets, positron emission tomographic studies) or by indirect measures (concentration of monoamine catabolites in plasma or CSF). We examine the hypothesis that chronic habitual smoking can be better understood in the context of two pharmacological factors: nicotine and reduced MAO activity. We speculate that MAO inhibition by compounds found in either tobacco or tobacco smoke can potentiate nicotine's effects. Based on this concept, more effective anti-smoking drug strategies may be developed. As a practical consequence of tobacco smoke's MAO-inhibitory properties, comparative psychiatric research studies need to screen and control for tobacco use.
Posted by janejj on June 10, 2003, at 17:50:39
In reply to Nicotine and brain chemicals, posted by tina on June 9, 2003, at 18:22:40
Yeah its supposed to increase Dopamine I think and thats why it makes you feel happy, I get the same thing...though i only have one once in a blue moon.
janejj
Posted by Ron Hill on June 10, 2003, at 19:34:15
In reply to Re: Nicotine and brain chemicals, posted by samplemethod on June 10, 2003, at 6:30:52
Sample,
> I would be interested in finding scientific evidence that nicotine is a MAO-B inhibitor. My impression was the cigarettes, or more correctly something within the cigarettes when smoked, actually affects MAO-B. It may well be nicotine, but I havent seen any proof of that yet.
According to this study, it's not nicotine; it's 2-Naphthylamine. It's also a carcinogen.
2-Naphthylamine, a compound found in cigarette smoke, decreases both monoamine oxidase A and B catalytic activity.
Hauptmann N, Shih JC.
Department of Molecular Pharmacology and Toxicology, School of Pharmacy, University of Southern California, Los Angeles, USA. hauptman@neotherapeutics.com
Cigarette smokers exhibit a lower monoamine oxidase (MAO; EC 1.4.3.4) activity than nonsmokers. MAO is located in the outer membrane of mitochondria and exists as two isoenzymes, MAO A and B. MAO A prefers 5-hydroxytryptamine (serotonin), and MAO B prefers phenylethylamine (PEA) as substrate. Dopamine is a substrate for both forms. 2-Naphthylamine is a carcinogen found in high concentrations in cigarette smoke. The results of this study show that 2-naphthylamine has the ability to inhibit mouse brain MAO A and B in vitro by mixed type inhibition (competitive and non-competitive). The Ki for MAO A was determined to be 52.0 microM and for MAO B 40.2 microM. The inhibitory effect of 2-naphthylamine on both MAO A and B catalytic activity, supports the hypothesis that smoking decreases MAO activity in vivo, instead that smokers with lower MAO activity are more prone to become a smoker.
PMID: 11233991 [PubMed - indexed for MEDLINE]
Posted by Caleb462 on June 10, 2003, at 22:17:52
In reply to Re: Nicotine and brain chemicals » samplemethod, posted by Ron Hill on June 10, 2003, at 19:34:15
I think the MAOI inhibition is a BIG part of tobacco dependence. In animal models, nicotine itself is only about as addictive as caffeine and pseudoephedrine.
Posted by tina on June 12, 2003, at 22:17:18
In reply to Re: Nicotine and brain chemicals--HELP » tina, posted by Larry Hoover on June 9, 2003, at 22:41:45
thanks Larry. I understood much more. I appreciate your indulgence and your patience.
I'm chain smoking these days so I'm glad I'm at least getting something productive out of it.
(wink wink)
thanks again
tina
This is the end of the thread.
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