Abstract
The ability of rat brain (minus cerebellum) homogenates to deamidate arachidonyl ethanolamide (anandamide) was determined with a custom-synthesized substrate, arachidonyl ethanolamide-[1-3H] ([3H]anandamide). Conditions whereby initial velocities were measured were established. The homogenates deamidated anandamide with a Km value of 0.8 μM and a Vmax value of 1.73 nmol · (mg protein)−1 · min−1. The deamidation of 2 μM [3H]anandamide was inhibited by phenylmethylsulfonyl fluoride and arachidonyl trifluoromethyl ketone with IC50 values of 3.7 and 0.23 μM, respectively. Ibuprofen inhibited anandamide deamidation in a mixed fashion, withKi and K′i values of 82 and 1420 μM. At an anandamide concentration of 2 μM, the IC50 values (in μM) of a series of compounds related in structure to ibuprofen were as follows: suprofen, 170; ibuprofen, 270; fenoprofen, 480; naproxen, 550; ketoprofen, 650; diclofenac, ∼1000. Sulindac produced 27% inhibition at a concentration of 1000 μM, whereas isobutyric acid, hydrocinnamic acid, acetylsalicylic acid and acetaminophen were essentially inactive at concentrations ≤ 1 mM. We conclude that ibuprofen inhibits anandamide deamidation at pharmacologically relevant concentrations and that there is some specificity to the inhibition produced by ibuprofen and suprofen.
Footnotes
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Send reprint requests to: Dr. Christopher J. Fowler, Department of Pharmacology, Umeå University, S-901 87 Umeå, Sweden.
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↵1 This work received financial support from the Research Fund of the Medical Faculty, University of Umeå, and the Joint Committee, North Health Region, Sweden.
- Abbreviations:
- Anandamide
- arachidonyl ethanolamide
- PMSF
- phenylmethylsulfonyl fluoride
- NSAID
- nonsteroidal anti-inflammatory drug
- COX
- cyclooxygenase
- Received November 25, 1996.
- Accepted July 2, 1997.
- The American Society for Pharmacology and Experimental Therapeutics
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