Evidence is building that part of the insensitivity to alcohol-related intoxication seen in adolescents may be related to the propensity of the adolescent brain to adapt very quickly to the presence of alcohol within a given exposure episode--a phenomenon termed “acute tolerance” (Mellanby, 1919). Basic science studies have shown that this rapid, within-session adaptation to a variety of intoxicating effects of alcohol is much more prevalent in young organisms than in adults (e.g., Silveri & Spear, 1998; Varlinskaya & Spear, 2006) and may be related in part to the developmentally enhanced expression of glutamate NMDA receptor systems discussed earlier (Silveri & Spear, 2004). Acute tolerance is not the entire story, however, in that blocking expression of acute tolerance does not eliminate expression of age differences in alcohol sensitivity (Silveri & Spear, 2002, 2004).
