Into The Wild...J'ai vécu six mois en ermite au bord du lac Baïkal

Marc a écrit :
Belles photos par Thomas Goisque
Photo 82, j'ai bien aimé le cabestan fait d'un tronc fiché dans un trou de glace, et d'une planche. Mais il y a fallu aussi les leviers.

C'est fou les manutentions que j'ai réussi avec des leviers.
Modifié il y a 11 ans
… tirer une clope
talonlibre a écrit :
… une clope et une vodka, ou peut-être un bon cigare cubain

Je l'avais signalé d'abord pour Bachi, puis à nouveau pour ma fille.

http://www.acnp.org/g4/GN401000167/Default.htm

Pathophysiology of Tobacco Dependence

Je vous fais grâce de l'extrait de l'article, juste les titres.

Pathophysiology of Tobacco Dependence

Jack E. Henningfield, Leslie M. Schuh, and Murray E. Jarvik

INTRODUCTION


NATURAL HISTORY AND CLINICAL COURSE


Epidemiology and Trends


Adolescent Nicotine Dependence


Severity of Nicotine Dependence


Non-Drug-Related Factors


Nicotine Delivery System




NEUROPHARMACOLOGY

Chemistry


Tolerance


Physical Dependence


Pharmacokinetics and Pharmacodynamics


Neurophysiology


Mechanisms of Reinforcement

Tolerance and dependence development are not sufficient to establish compulsive smoking of cigarettes, or any other drug for that matter (73). The drug also must be self-administered frequently enough for its reinforcing effects to condition the behavior. Such conditioning processes are maximally effective when the drug effect is discrete, paired with readily discriminable stimuli, and follows a specific behavior within a few seconds (73). The paradigm is optimal for smoking to become powerfully conditioned because each cigarette provides approximately 10 nicotine reinforcers, each carried by a sensorally sating cloud of smoke and delivered to the brain in seconds. Tolerance and physical dependence potentiate the process by establishing a motivational state in the individual which did not preexist. Thus, smoking is reinforced both by the direct positively reinforcing actions of nicotine on the brain and by the necessity of continued nicotine administration to prevent withdrawal symptoms.

In addition to the direct actions of nicotine to strengthen behavior and alleviate withdrawal symptoms, cigarette smokers commonly report benefits that may be at least partially attributable to nicotine. It may not be possible to completely dissociate transient relief of withdrawal from nicotine effects that people with certain vulnerabilities or deficits find addressed by nicotine, but it is important to be aware that smoking cessation will lead to a variety of potential unfulfilled needs that can contribute to relapse. For example, some people claim that smoking enhances their ability to handle stress, helps to control appetite and weight, increases the pleasure of leisure activities such as reading and listening to music, and facilitates social interactions.

At least three kinds of nicotine effects, then, can contribute to the development of dependence: (i) Nicotine delivery produces reinforcing effects mediated by reward systems in the brain; (ii) tolerance and physical dependence are produced such that nicotine abstinence is accompanied by adverse effects; and (iii) at least those dependent on nicotine may derive useful effects on mood, appetite, and cognition. These effects are not mutually exclusive, and they often interact.

When nicotine replacement therapy is viewed from the foregoing perspective, we see that very little of the cigarette is actually replaced by the nicotine delivery medications. Therefore, patients may be disappointed when they find that the medications are neither as pleasurable nor as quickly satisfying as cigarettes. Nonetheless, our understanding of the pathophysiology of tobacco dependence has progressed to the point that it has been possible to develop nicotine replacement pharmaceuticals with impact on the disease process. These medications may not satisfy all the wants and desires of the cigarette smoker, but they can provide many patients with what they need to achieve tobacco abstinence.

Modifié il y a 11 ans
Du même, voir aussi :
http://www.expemag.com/pdf/sylvain-tesson.pdf
Modifié il y a 11 ans