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Structural determinants for recognition and translocation by the anandamide transporter
D Piomelli1, M Beltramo, S Glasnapp
1The Neurosciences Institute, San Diego, CA 92121, USA. piomelli@uci.edu
Summary
Anandamide (arachidonylethanolamide) transport relies on specific structural features, including a bent hydrophobic tail and multiple cis double bonds for efficient cell membrane translocation. This understanding aids in developing targeted inhibitors.
Area of Science:
- Neuroscience
- Biochemistry
- Pharmacology
Background:
- Anandamide (arachidonylethanolamide) is an endogenous cannabinoid lipid whose actions are terminated by uptake and hydrolysis.
- Anandamide uptake is mediated by a high-affinity, Na+-independent transporter inhibited by AM404.
Purpose of the Study:
- To investigate the structural requirements for substrate recognition and translocation by the anandamide transporter.
- To identify key molecular features influencing anandamide transport.
Main Methods:
- Utilized competition experiments with anandamide analogs.
- Conducted uptake experiments with radioactively labeled substrates.
- Examined substrate translocation across a human astrocytoma cell line.
Main Results:
- Substrate recognition requires a polar, nonionizable head group with a distal hydroxyl moiety.
- The carboxamide group is favorable but replaceable (e.g., ester), acting as a hydrogen acceptor.
- Optimal translocation necessitates at least four cis double bonds in the fatty acid chain, suggesting a folded hairpin conformation for transport.
Conclusions:
- Defined the structural requisites for anandamide transport, including head group characteristics and fatty acid chain unsaturation.
- Findings may guide the development of selective anandamide transporter inhibitors for therapeutic applications.