Nicotine Physiology
Nicotine is a chemical that can be absorbed into the blood via the lungs, the oral mucosa or the skin. Once in the blood, nicotine can rapidly travel into the nervous system. According to the National Institute on Drug Abuse, once nicotine is in the nervous system it binds to special proteins called nicotinic receptors. These receptors are designed to respond to the chemical acetylcholine, which the nervous system uses to send signals between neurons and from neurons to muscles. As a result, exposure to nicotine results in altered chemical signaling in the nervous system.
Nicotine Addiction
The nervous system has the ability to adapt to changes in the chemistry of its neurons. After repeated and prolonged nicotine exposure, some of the nicotinic receptors are removed to adjust for the enhanced signaling that nicotine causes. However, if nicotine use is stopped (by stopping the consumption of tobacco), this disrupts the now-altered brain chemistry. As a result, the brain goes into withdrawal because it's experiencing a lack of signaling from the nicotinic receptors. This is the cause of the physical withdrawal symptoms and the craving for nicotine. The purpose of nicotine gum is to replace the nicotine, helping relieve the chemical withdrawal while still avoiding tobacco use.
Nicotine Gum Use
As Medline explains, nicotine gum can be chewed either on a regular schedule or when a former tobacco user feels nicotine cravings. The gum itself contains nicotine which, when chewed, is absorbed by tissue in the mouth. It works best when the gum is chewed for a short period. When it generates a tingling sensation, it should be pressed up against the inside of the cheek; that's the tissue that can absorb the nicotine. When the tingling stops, the gum can be chewed more so that the process can be repeated.
