Final answer:
Nicotine increases the release of dopamine in the brain by stimulating neurons, which results in enhanced pleasurable sensations and contributes to addiction. This stimulation can lead to a dependence on nicotine to continue feeling pleasure and avoid withdrawal symptoms.
Step-by-step explanation:
The end result of nicotine action in the dopamine reward pathway is the increase in the release and action of dopamine in the brain. When nicotine binds to nicotinic acetylcholine receptors on neurons, it leads to increased firing of these neurons which results in a greater release of dopamine. Dopamine is a neurotransmitter associated with feelings of pleasure, movement, and motivation. The heightened presence of dopamine stimulates the pleasure centers of the brain, contributing to nicotine's addictive properties.
Over time, the constant stimulation of the reward pathway by nicotine can lead to addiction, where individuals continue to use nicotine to maintain the pleasurable sensations and avoid withdrawal symptoms. This can further contribute to the disruption of natural dopamine regulation and may cause individuals to seek greater quantities of nicotine or other substances to achieve the desired effect, perpetuating the cycle of addiction.