Disaggregation of brain polysomes after LSD in vivo. Involvement of LSD-induced hyperthermia.

LSD-induced hyperthermia is implicated in the brain-specific disaggregation of polysomes which is induced following intravenous administration of the drug to rabbits. Both LSD-induced hyperthermia and brain polysome disaggregation were found to increase in parallel under conditions which accentuated the effect of the drug on brain protein synthesis. Pretreatment with neurotransmitter receptor blockers or placing the animal at an ambient temperature of 4 degrees C after LSD administration prevented both hyperthermia and brain polysome disaggregation. The administration of apomorphine, which causes hyperthermia in rabbits also caused disaggregation of brain polysomes. Direct elevation of the body temperature to levels similar to that found after LSD was achieved by placing animals at an ambient temperature of 37 degrees C. Under these conditions a brain-specific disaggregation of polysomes resulted which was not due to RNAase activation. After either LSD or direct heating, the brain polysome shift was associated with a relocalization of polyadenylated mRNA from polysomes to monosomes as determined by [3H]polyuridylate hybridization. Since polysome disaggregation was found only in brain, it appears that the brain may be more sensitive to elevations in body temperature compared to other organs.