Jumat, 08 Oktober 2010

Why Cigarettes Cause Addiction

( - Everyone knows that smoking is bad for health. Everyone knows that smoking causes cancer, heart disease, stroke, emphysema, bronchitis, vascular disease, cataracts, impotence, and other health problems. World Health Organization (WHO) estimates that more than four million deaths each year caused by smoking. However, the number of smokers in the world is increasing every year and anyone who tried to quit (smoking) know that it is very difficult to do so. And we know that the cigarettes smoked contain nicotine which is a hazardous chemical into the membrane in a gentle and into their bodies.

So why can nicotine addiction that can make a big impact even though only a little smoke? The answer is nicotine stimulates chemicals that control the feeling of happiness in the brain, dopamine (DA). Part of the mechanism behind the ability of nicotine to maintain the central stimulation of the brain even after only a few smoking described by Dr. Daniel McGehee and Hulbert's Mansvelder, at the University of Chicago, in an article published in Neuron in 2000 (1).
When nicotine binds certain nerves in the brain, nerves are quickly pulled out some DA, which acts in an area that gave the "reward" in the brain and has been very enjoyable. However, cells that are sensitive to this stimulus loses its sensitivity to nicotine in a short time, just seconds to several minutes, and these cells stops producing DA. End of story, happy? No. When turned, the same type of cells to nicotine also occur on presynaptic terminals in the same brain regions. When activated by nicotine, they cause the release of the signal molecule, glutamine. This new release of glutamine can occur in certain DA nerves to stimulate them to release more DA. DA nerve activation by glutamine resulted continuation DA release a few hours, in the long term potential to stimulate input. So even if a person only consumes nicotine for several minutes, the effect of fun can continue for some time in this way. This may explain the long-term sense of fun parts of the brain reward induced by consuming less nicotine. The overall incidence uintuk similar mechanism is seen during learning and memory and may be an important first step in the development of addiction.
The second part of the puzzle is why the stimulation of DA release was not immediately stop. As described by the same group in an article published in Neuron in 2002 (2), the body has a mechanism to stop the production of DA and the mechanism is stimulated by nicotine. Nicotine binding and activate cells that are sensitive then release the neurotransmitter in the central nervous system preventive, gamma-aminobutyric acid (GABA). Briefly. Yes, unfortunately, the cells are sensitive to nicotine and then turn on the release of GABA which acts to stop the release of DA which is also non-reactive to nicotine immediately after touching. However, to enable the release of glutamine to continue and activate the release of DA may continue as a reduction of GABA release. So the longer time, resulting in more DA is produced through the release of glutamine opium nicotine through cell activation.
So it seems a strong desire to nicotine in cigarettes can be explained simply by the crib with drug-sensitive cells that would surround. At first discovered nicotine-sensitive cells in the nerves of the DA who likes to be tied to him and then stimulated to release DA. But they soon tired because of nicotine, and no longer stimulated by it. Then the sensitive cell-bound and sustain addiction to nicotine, releasing glutamine, and causes the release of DA, for several hours. But the third, there are sensitive cells that bound nicotine and activated to release a strong negative signal, GABA. But this sensitive cells soon lose interest and leave the nicotine to interact mainly with glutamatergic path that causes arousal.
Thus, the complexity of the interplay between the molecules came a strong desire for someone to smoke. Addiction which destroys life is created from molecular events like this. It is necessary for us to obey the dictator of molecular interaction, where we have to do anything to maintain our level of dopamine? It is not possible, then thinking and a strong desire someone, say, do not become slaves of dirt molecules, or the choice to live free from drugs, may alter the consequences of the interaction of these molecules? Get strong thinking, self-determination, changing one's reaction to the cigarette, so he no longer finds pleasure in it, but a reluctant and ignore it? Why do some people immediately and completely addicted after only a few cigarettes smoked, while others smoke for a week and throughout his life? Why do some older smokers really are powerless when it comes time to try to stop the habit, but others can stop it with ease, and others through repeated failures until they finally succeed? It may be true that science says, that our mental state, our desire for a pack of cigarettes nicotine, can be stimulated by the interaction of molecules caused by the binding of drugs in sensitive cells in our brain, is not it also true that we are not bound, not necessarily obey, to ignore or rise above the tyranny of this? Perhaps humanity is more than just a packet of molecules.
(1) Mansvelder, H.D. and McGehee, D.S. (2000). The long-term potential of opiate input into the brain reward areas by nicotine. Neuron 27, 349-357.
(2) Mansvelder, HD, Keath, JR, and McGehee, DS (2002). Synaptic mechanisms underlying the induction of nicotine stimulation of the brain reward. Neuron 33, 905-919.

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