Recent evidence implicates anandamide as the endogenous ligand for the cannabinoid receptor. One purpose of this study was to determine the structural requirements for anandamide's receptor interaction and the influence of phenylmethylsulfonyl fluoride (PMSF), an enzyme inhibitor, on receptor affinity. A second objective was evaluation of the correlation between affinities of the analogs and in vivo pharmacological activities. The ability of anandamide and analogs to displace [3H]- CP 55,940 was determined by a filtration assay. Displacement curves for anandamide in the presence of PMSF produced a Ki of 89 ± 10 nM; without PMSF the Ki increased to 5400 ± 1600 nM. Anandamide analogs were evaluated for their ability to produce antinociception and hypomotility. The levels of saturation and substituents for the ethanolamide and hydroxyl groups of the anandamide structure were critical to receptor affinity and in vivo potency. Increasing the length of the N-substituent by one or two carbons decreased receptor binding affinity. Methylations at carbons 2 and l' produced compounds stable in the absence of PMSF. Addition of larger alkyl groups at these positions or nitrogen methylation reduced receptor affinity and behavioral potency. These results indicate that methylations at specific carbons of anandamide confer stability in vitro. A final objective was to characterize anandamide's binding to the cannabinoid receptor in the CNS. Anandamide's receptor binding affinities and binding densities, as determined from autoradiographic experiments in rat brain, from selected brain areas were compared to the receptor binding densities and patterns of two other compounds, CP 55,940 and SR 147116A, that bind to the central cannabinoid receptor. The lack of difference between receptor affinity, receptor distribution and parallelism of the displacement curves indicate that anandamide, SR 141716A and CP 55,940 are binding to the same receptor in the same manner.
| Identifer | oai:union.ndltd.org:vcu.edu/oai:scholarscompass.vcu.edu:etd-5394 |
| Date | 01 January 1996 |
| Creators | Adams, Irma Bateman |
| Publisher | VCU Scholars Compass |
| Source Sets | Virginia Commonwealth University |
| Detected Language | English |
| Type | text |
| Format | application/pdf |
| Source | Theses and Dissertations |
| Rights | © The Author |
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