The biological effects of nicotine occur due to its interaction with nerve cells in the body and brain. Nicotine interacts primarily with the autonomic nervous system, which controls involuntary body responses. The body-wide distribution of the autonomic nervous system explains the numerous and diverse effects of nicotine in various organ systems. Additionally, nicotine can provoke varying biological effects in the same tissues at different concentrations.
Adrenalin Release
Nicotine has a direct effect on the adrenal glands, causing a release of adrenaline, the "fight or flight" hormone, reports the National Institute on Drug Abuse. Adrenaline has potent effects on several body tissues, including triggering a surge in blood glucose.
Cardiovascular Stimulation
Nicotine has stimulating effects on the cardiovascular system, notes the medical reference text "AHFS Drug Information." Heart rate and the force of heart muscle contractions increase under the influence of nicotine. The volume of blood pumped per beat increases with nicotine stimulation. Blood pressure also rises due to constriction of the blood vessels. Heart rate returns to a normal level more quickly than does the blood pressure after exposure to nicotine.
Respiratory Stimulation
The respiratory rate temporarily increases with nicotine exposure, according to "AHFS Drug Information." The respiratory rate returns to a normal level as the liver metabolizes and deactivates nicotine.
Dopamine Release
Nicotine travels to the brain within 10 seconds of inhaling tobacco smoke, notes the National Institute on Drug Abuse. Once in the brain, dopamine causes a release of the neurotransmitter dopamine. The release of dopamine in the pleasure and reward center of the brain reinforces smoking behavior. As with other drugs of abuse, smokers repetitively seek the pleasure and reward sensations triggered by nicotine's effects on the brain.
Immunosuppression
Nicotine has potent suppressive effects on the immune system. In a 2000 research study published in "The Journal of Pharmacology and Experimental Therapeutics," Roma Kalra, Ph.D., and colleagues report that nicotine inhibits both antibody production and immune cell activity in the body tissues.
Anti-inflammatory Effects
Closely related to its immunosuppressive effects, nicotine also exhibits anti-inflammatory effects. In a 2006 study published in "Journal of Leukocyte Biology," Isabelle Cloëz-Tayarani, Ph.D., and Jean-Pierre Changeux, Ph.D., report that nicotine suppresses the release of inflammation-stimulating chemicals. The authors postulate that the inhibition of healthy inflammation may be a contributing factor in the development of smoking-related illnesses such as chronic obstructive pulmonary disease, bronchitis, pneumonia, asthma and lung cancer.
Gastrointestinal Stimulation
Nicotine stimulates the motility of the gastrointestinal system through its effects on the central autonomic nervous system, reports "AHFS Drug Information." In people who do not smoke, exposure to nicotine may cause nausea, vomiting and diarrhea. Smokers quickly become tolerant to these effects through a series of nervous system adaptations.
References
- National Institute on Drug Abuse: NIDA InfoFacts--Cigarettes and Other Tobacco Products
- National Institute on Drug Abuse: Is Nicotine Addictive?
- "The Journal of Pharmacology and Experimental Therapeutics"; Effects of Cigarette Smoke on Immune Response: Chronic Exposure to Cigarette Smoke Impairs Antigen-Mediated Signaling in T Cells and Depletes IP3-Sensitive Ca2+ Stores; Roma Kalra, Ph.D., et al.; April 2000
- "Journal of Leukocyte Biology"; Nicotine and Serotonin in Immune Regulation and Inflammatory Processes; Isabelle Cloëz-Tayarani, Jean-Pierre Changeux; November 2006
- "AHFS Drug Information 2008"; American Society of Health-System Pharmacists; 2008
