## Neurochemistry of Alcohol Withdrawal ### GABA Dysregulation in Withdrawal **Key Point:** Alcohol is a positive allosteric modulator of GABA~A~ receptors, enhancing inhibitory neurotransmission. Chronic alcohol use leads to downregulation of GABA~A~ receptors and reduced GABA synthesis. Upon abrupt cessation, loss of alcohol's GABAergic enhancement combined with reduced receptor density results in a net loss of inhibitory tone. ### Mechanism of Hyperexcitability 1. Chronic alcohol → decreased GABA~A~ receptor expression and function 2. Alcohol withdrawal → removal of positive allosteric modulation 3. Result: unopposed excitatory (glutamatergic) activity 4. Clinical manifestation: tremor, seizures, autonomic hyperactivity, delirium tremens ### Compensatory Changes During Dependence | System | Change with Chronic Use | Effect on Withdrawal | |--------|------------------------|-----------------------| | GABA~A~ | Downregulation | Loss of inhibition | | Glutamate | Upregulation | Unopposed excitation | | NMDA receptors | Increased expression | Enhanced excitatory drive | **High-Yield:** This GABAergic deficit is why benzodiazepines (GABA~A~ agonists) are the first-line treatment for alcohol withdrawal — they restore inhibitory tone and prevent seizures and delirium tremens. **Clinical Pearl:** The severity of withdrawal correlates with the degree of GABA~A~ receptor downregulation, explaining why heavy, long-term drinkers experience more severe withdrawal syndromes.
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