Changes

== Nicotine ==

== Nicotine ==

Nicotine is an alkaloid in tobacco that is responsible for the addictive nature of cigarette smoking and other tobacco use.  Regular nicotine consumption leads to [[tolerance]]<ref>Porchet, H. C., Benowitz, N. L., & Sheiner, L. B. (1988).  Pharmacodynamic model of tolerance:  Application to nicotine.  ''Journal of Pharmacology & Experimental Therapeutics, 244'', 231-236</ref> (i.e., higher doses are required to achieve the same effect), and [[withdrawal]]<ref>Hughes, J.R., Higgins, S.T., & Bickel, W.K. (1994).  Nicotine withdrawal versus other drug withdrawal syndromes: Similarities and dissimilarities.  ''Addiction, 89'', 1461-1470</ref> symptoms (e.g., irritability, restlessness, nicotine cravings) occur when use is discontinued.  Intake elicits acute increases in heart rate and blood pressure, as well as respiratory rate.  Nicotine reaches the brain about seven seconds after it is inhaled in cigarette smoke, and stimulates the release of a number of [[neurotransmitters]], including [[dopamine]], [[norepinephrine]], [[serotonin]], and [[acetylcholine]].  The increased availability of these chemicals in the brain leads to feelings of pleasure and mild euphoria, as well as increased alertness and concentration.  The half-life of nicotine is approximately two hours.

Nicotine is an alkaloid in tobacco that is responsible for the addictive nature of cigarette smoking and other tobacco use.  Regular nicotine consumption leads to [[tolerance]]<ref>Porchet, H. C., Benowitz, N. L., & Sheiner, L. B. (1988).  Pharmacodynamic model of tolerance:  Application to nicotine.  ''Journal of Pharmacology & Experimental Therapeutics, 244'', 231-236</ref> (i.e., higher doses are required to achieve the same effect), and [[withdrawal]]<ref>Hughes, J.R., Higgins, S.T., & Bickel, W.K. (1994).  Nicotine withdrawal versus other drug withdrawal syndromes: Similarities and dissimilarities.  ''Addiction, 89'', 1461-1470</ref> symptoms (e.g., irritability, restlessness, nicotine cravings) occur when use is discontinued.  Intake elicits acute increases in heart rate and blood pressure<ref>Benowitz, N.L., Jacob, P., Jones, R.T., & Rosenberg, J. (1982).  Interindividual variability in the metabolism and cardiovascular effects of nicotine in man.  ''Journal of Pharmacology & Experimental Therapeutics, 221'', 368-372.''</ref>, as well as respiratory rate, but also decreases the volume of blood flow by causing the constriction of blood vessels.  Nicotine reaches the brain about seven seconds after it is inhaled in cigarette smoke, and stimulates the release of a number of [[neurotransmitters]], including [[dopamine]], [[norepinephrine]], [[serotonin]], and [[acetylcholine]].  The increased availability of these chemicals in the brain leads to feelings of pleasure and mild euphoria, as well as increased alertness and concentration.  The half-life of nicotine is approximately two hours.

Nicotine has also been found to be useful in treating certain disorders.

Nicotine has also been found to be useful in treating certain disorders.