Posted by Quintal on August 29, 2007, at 9:58:37
In reply to Re: EMSAM with transdermal nicotine for ADD contro, posted by cumulative on August 28, 2007, at 23:37:02
>Tolerance could definitely be an issue. Someone told me, though, that nicotine will activate stimulant reverse tolerance for dopamine.
Yeah, according to Wiki, nicotine seems to be one of the few substances that induces reverse tolerance.
____________________________________________________In many studies it has been shown to be more addictive than cocaine and heroin, though chronic treatment has an opposite effect on reward thresholds. Like other physically addictive drugs, nicotine causes down-regulation of the production of dopamine and other stimulatory neurotransmitters as the brain attempts to compensate for artificial stimulation. In addition, the sensitivity of nicotinic acetylcholine receptors decreases. To compensate for this compensatory mechanism, the brain in turn upregulates the number of receptors, convoluting its regulatory effects with compensatory mechanisms meant to counteract other compensatory mechanisms. The net effect is an increase in reward pathway sensitivity, opposite of other drugs of abuse (namely cocaine and heroin, which reduces reward pathway sensitivity). This neuronal brain alteration persists for months after administration ceases. Due to an increase in reward pathway sensitivity, nicotine withdrawal is relatively mild compared to ethanol or heroin withdrawal. Also like other highly addictive drugs, nicotine is addictive to many animals besides humans. Mice will self-administer nicotine and experience behavioral unpleasantries when its administration is stopped. Gorillas have learned to smoke cigarettes by watching humans, and have similar difficulty quitting.
http://en.wikipedia.org/wiki/Nicotine#Dependence
--------------------------------------------------Research suggests that when smokers wish to achieve a stimulating effect, they take short quick puffs, which produces a low level of blood nicotine. This stimulates nerve transmission. When they wish to relax, they take deep puffs, which produce a high level of blood nicotine, which depresses the passage of nerve impulses, producing a mild sedative effect. At low doses, Nicotine potently enhances the actions of norepinephrine and dopamine in the brain causing a drug effect typical of pyschostimulants. At higher doses nicotine enhances the effect of serotonin and opiate activity, producing a calming, pain killing effect. Nicotine is unique in comparison to most drugs, as its profile changes from stimulant to sedative/pain killer in increasing dosages and use.
Nicotine gum and patches are available, usually in 2 mg or 4 mg doses of gum, that do not have all the other ingredients in smoked tobacco. They appear to be not as addictive or as pleasurable, and perhaps have fewer side effects [citation needed]. Whether all the other psychoactive effects also occur has not been well studied.
http://en.wikipedia.org/wiki/Nicotine#Psychoactive_Effects
__________________________________________________Q
poster:Quintal
thread:779241
URL: http://www.dr-bob.org/babble/20070824/msgs/779512.html