High Affinity Electrophilic and Photoactivatable Covalent Endocannabinoid Probes for the CB1 Receptor
摘要:
We have designed and synthesized the first two high affinity covalent anandamide probes for the CB1 receptor by introducing either an electrophilic isothiocyanato or a photoactivatable azido group at the terminal carbon of the arachidonic acid moiety. The headgroup of these anandamide analogues was optimized by using a cyclopropylamide substituent to impart optimal CB1 affinity. Both 20-isothiocyanato-eicosa-5,8,11,14-tetraenoic acid cyclopropylamide (1, AM3677) and 20-azido-eicosa-5,8,11,14-tetraenoic acid cyclopropylamide (2, AM3661) exhibited high selectivities for the CB 1 receptor with K-i values of 1.3 and 0.9 nM, respectively. Using suitable experimental conditions, both ligands were shown to covalently label the CB1 receptor with high efficiency. These two covalent probes for the endocannabinoid CB1 binding site open the door for exploring the ligand binding motifs involved in the activation of the CB1 receptor by its endogenous ligand, anandamide.
High Affinity Electrophilic and Photoactivatable Covalent Endocannabinoid Probes for the CB1 Receptor
摘要:
We have designed and synthesized the first two high affinity covalent anandamide probes for the CB1 receptor by introducing either an electrophilic isothiocyanato or a photoactivatable azido group at the terminal carbon of the arachidonic acid moiety. The headgroup of these anandamide analogues was optimized by using a cyclopropylamide substituent to impart optimal CB1 affinity. Both 20-isothiocyanato-eicosa-5,8,11,14-tetraenoic acid cyclopropylamide (1, AM3677) and 20-azido-eicosa-5,8,11,14-tetraenoic acid cyclopropylamide (2, AM3661) exhibited high selectivities for the CB 1 receptor with K-i values of 1.3 and 0.9 nM, respectively. Using suitable experimental conditions, both ligands were shown to covalently label the CB1 receptor with high efficiency. These two covalent probes for the endocannabinoid CB1 binding site open the door for exploring the ligand binding motifs involved in the activation of the CB1 receptor by its endogenous ligand, anandamide.
One aspect of this disclosure relates generally to lipid compounds that exert diverse effects in the endocannabinoid system, such as regulating CB1 and CB2 receptor or moderating other bio-macromolecules within the endocannabinoid system. Some of the compounds showed improved receptor binding affinity, and/or improved receptor subtype selectivity, and improved bio-stability. Some of the compounds exhibit activities to regulate the enzymes that moderate the bio-disposal of endogenous cannabinoids, such as the fatty acid amide hydrolase (FAAH). Some of the compounds exhibit activities to inhibit the anandamide transporter. Other aspects of the invention are pharmaceutical preparations employing these ligands and methods of administering therapeutically effective amounts of the preparations to provide a physiological effect.