12.2 : 中枢神经抑制剂：酒精和尼古丁

CNS depressants like alcohol and nicotine mediate their actions via ionotropic receptors by distinct mechanisms.

Ethanol, primarily found in alcoholic beverages, acts as a GABA agonist and inhibits glutamate's excitatory actions, causing impaired motor control and sedation.

Chronic ethanol use can lead to tolerance and physical dependence, resulting in withdrawal symptoms like anxiety, tremors, and seizures.

Alcohol dependence is treated with detoxification and pharmacotherapy, using drugs like benzodiazepines. Further, disulfiram creates unpleasant reactions to alcohol consumption and mitigates cravings.

Additionally, naltrexone, a competitive, long-acting opioid antagonist, and acamprosate, an NMDA regulator, also help reduce alcohol cravings.

Nicotine, found in tobacco, acts as a CNS stimulant and a depressant. It stimulates the nicotinic acetylcholine receptors in the CNS, leading to dopamine release. This creates feelings of relaxation and pleasure.

Nicotine withdrawal can cause irritability, restlessness, and cravings.

To assist nicotine deaddiction, varenicline, a partial nicotinic receptor agonist, alleviates withdrawal symptoms.