In animal studies, self-administration of nicotine is most likely suppressed by:

Self-administration of nicotine is most likely suppressed by blocking dopaminergic pathways because nicotine primarily exerts its reinforcing effects through the activation of the brain's reward system, which is heavily reliant on dopamine. Nicotine stimulates nicotinic acetylcholine receptors, leading to increased dopamine release in key areas like the nucleus accumbens. When dopaminergic pathways are blocked, the reinforcement associated with nicotine administration diminishes, making the behavior less likely to be repeated. This biological mechanism underscores the pivotal role of dopamine in motivation and reward-seeking behaviors, especially in relation to substance use. Therefore, interventions targeting the dopaminergic system can effectively reduce nicotine self-administration.