Lysergic acid diethylamide and [-]-2,5-dimethoxy-4-methylamphetamine increase extracellular glutamate in rat prefrontal cortex.
Level 5 - mechanism / opinion, no new human data
Animal research (in vivo rat microdialysis study)
PubMed 15364028 · doi:10.1016/j.brainres.2004.07.044
What was done
Researchers measured extracellular glutamate concentrations in the prefrontal cortex of rats using in vivo microdialysis. They tested systemic administration of lysergic acid diethylamide (LSD; 0.1 mg/kg, i.p.) alone and following pretreatment with the 5-HT2A antagonist M100907 (0.05 mg/kg, i.p.), systemic administration of [-]-2,5-dimethoxy-4-methylamphetamine (DOM; 0.6 mg/kg, i.p.), and direct application of LSD (10 microM) to the prefrontal cortex via reverse dialysis.
What was found
Systemic LSD induced a time-dependent increase in prefrontal cortex glutamate that was blocked by M100907, though the abstract reports no specific numerical values for this effect. Systemic DOM increased glutamate to 206% above saline-treated controls. Direct reverse dialysis of LSD into the prefrontal cortex produced a rapid increase in glutamate that remained elevated after drug infusion was discontinued.
Why it matters
The findings provide direct in vivo evidence that structurally distinct hallucinogens increase cortical glutamate release via 5-HT2A activation, highlighting a potential shared neurochemical pathway.
Limits
The abstract does not report the number of animals used (n) or exact numerical values and variance for the LSD experiments. Findings in rodents may not directly translate to human cortical function or subjective psychedelic effects.
Cited by
- supports The downstream neurochemical effects of classic hallucinogens like psilocybin are mediated through the glutamate system.