Nicotine is an addictive drug that occurs naturally in tobacco and other plants of the Solanaceae family, explains the "Encyclopedia of Drugs, Alcohol & Addictive Behavior." The physical effects of nicotine use vary depending on dose, frequency of use, existing nicotine tolerance and method by which the drug is put into the body.
Decrease in Appetite
The textbook, "Neurobiology of Addiction," explains that nicotine decreases appetite overall and curbs cravings for sweets and foods that are rich in carbohydrates. Additionally, nicotine elevates the body's rate of fat metabolism. The text "Encyclopedia of Drugs, Alcohol & Addictive Behaviors" notes that nicotine's appetite-suppressing effects may be due to an increase in epinephrine release from the adrenal glands.
Cognitive Arousal
According to "Neurobiology of Addiction," nicotine has been shown to improve concentration, learning, alertness and problem-solving ability. However, a study published in a 2009 volume of "Psychopharmacology" suggests that nicotine-induced cognitive enhancement occurs only in chronic nicotine users. This study failed to see consistent improvement in cognition when nicotine was given sporadically to non-dependent subjects.
Increased Heart Rate
Some of nicotine's physiological actions are achieved through the stimulation of nerves that regulate the heart rate. According to the "Encyclopedia of Drugs, Alcohol & Addictive Behavior," nicotine has other effects on the cardiovascular system as well; it constricts peripheral and heart blood vessels, causing poor circulation and an increase in blood pressure.
Decrease in Tension
"Neurobiology of Addiction" notes that nicotine seems to reduce anxiety and relieve mild pain. Nicotine affects the skeletal muscles by decreasing muscle tone, which releases tension. The "Encyclopedia of Drugs, Alcohol & Addictive Behavior" attributes nicotine's ability to lower anxiety to changes in brain signaling that depends on the neurotransmitter serotonin. Nicotine's pain-relieving effects may be related to physiological mechanisms that are similar to the effects of opioids such as morphine and heroin.
Effects of Nicotine Overdose
High doses of nicotine have deleterious effects on the body, including nausea, vomiting, paralysis, respiratory depression, coma and severe cardiovascular impairment, according to the "Encyclopedia of Drugs, Alcohol & Addictive Behavior." Doses of nicotine that exceed 60 mg taken by mouth are considered fatal, according to "Neurobiology of Addiction."
References
- Encyclopedia of Drugs, Alcohol & Addictive Behaviors (3rd Edition); Pamela Korsmeyer and Henry R. Kranzler; 2008
- Neurobiology of Addiction; George F. Koob and Michel Le Moal; 2006
- Psychopharmacology; Chronic nicotine improves cognitive performance in a test of attention but does not attenuate cognitive disruption induced by repeated phencyclidine administration; N. Amitai and A. Markou; January 2009
