Diurnal variation of arachidonoylethanolamine, palmitoylethanolamide and oleoylethanolamide in the brain of the rat
Laboratory studyOther animals
- Design
- Laboratory study
- Subjects
- Rats, sampled over a 24-hour cycle
- Duration
- 24 hours
- What was measured
- Levels of anandamide, palmitoylethanolamide and oleoylethanolamide in cerebrospinal fluid, pons, hippocampus and hypothalamus, by HPLC/MS.
What the authors reported
This study found:
- In cerebrospinal fluid, all three compounds rose during the lights-on period and fell during the lights-off period.
- In the pons, all three compounds peaked during the dark phase.
- In the hippocampus, palmitoylethanolamide peaked at the start of the lights-off period; anandamide rose through the same period; oleoylethanolamide showed no diurnal pattern there.
- In the hypothalamus, palmitoylethanolamide and oleoylethanolamide peaked at the end of the lights-off period, while anandamide rose during the lights-on period.
- The authors propose these compounds build up in brain tissue during the lights-off period (when the rat is awake) and are then released into cerebrospinal fluid to reach target regions involved in feeding and sleep.
Limits of this study
Rat brain tissue and cerebrospinal fluid, not human data, and observational (levels measured, nothing administered). The proposed release mechanism is the authors' interpretation, not a finding directly measured in this study.
Source
PubMed 16434061 · doi:10.1016/j.lfs.2005.12.028
Entry checked against the abstract on PubMed on 2026-09-22. The dose shown is the dose the researchers used. It is not a recommendation. How to read this page.