Alcohol Intoxication: How Ethanol Affects the Brain and Body

Ethanol exerts dose-dependent effects via CNS depression:

1. GABAergic enhancement: Potentiates GABA_A receptors → sedation, anxiolysis, ataxia.
2. Glutamatergic inhibition: Blocks NMDA receptors → cognitive impairment, amnesia.
3. Dopamine release in nucleus accumbens: Reward, euphoria, reinforcement.
4. Cerebellar depression: Ataxia, dysmetria, dysarthria.
5. Cerebral cortex: Disinhibition, impaired judgment, slowed reaction time.

Additional Effects

• Gastric irritation: Nausea, vomiting (esp. empty stomach).
• Hepatic metabolism: ADH/ALDH → acetaldehyde (toxic) → acetate. Rate ~1 standard drink/hour. Excess → rising BAC.
• Diuresis: ADH suppression → dehydration, electrolyte imbalance.
• Sleep architecture disruption: Initial sedation → rebound fragmentation, reduced REM.

Individual Variability

Genetics (ADH/ALDH polymorphisms), body composition, sex, age, tolerance, food intake, medications. No safe level for driving; impairment begins at BAC >0.02%.