{"doi":"10.1101/2023.03.03.531053","title":"Pharmacological characterization of the endocannabinoid sensor GRAB <sub>eCB2.0</sub>","abstract":"Abstract Introduction The endocannabinoids ( eCBs ), 2-arachidonoylglycerol ( 2-AG ) and arachidonoyl ethanolamine ( AEA ), are produced by separate enzymatic pathways, activate cannabinoid receptors with distinct pharmacology, and differentially regulate pathophysiological processes. The genetically encoded sensor, GRAB eCB2.0 , detects real-time changes in eCB levels in cells in culture and preclinical model systems; however, its activation by eCB analogues produced by cells and by phyto-cannabinoids remains uncharacterized, a current limitation when interpreting changes in its response. This information could provide additional utility for the tool in in vivo pharmacology studies of phyto-cannabinoid action. Methods GRAB eCB2.0 was expressed in cultured HEK293 cells. Live cell confocal microscopy and high-throughput fluorescent signal measurements. Results 2-AG increased GRAB eCB2.0 fluorescent signal (EC 50 = 85 nM), and the cannabinoid 1 receptor ( CB 1 R ) antagonist, SR141617, decreased GRAB eCB2.0 signal ( SR1 , IC 50 = 3.3 nM), responses that mirror their known potencies at cannabinoid 1 receptors ( CB 1 R ). GRAB eCB2.0 fluorescent signal also increased in response to AEA (EC 50 = 815 nM), the eCB analogues 2-linoleoylglycerol and 2-oleoylglycerol ( 2-LG and 2-OG , EC 50 s = 1.5 and 1.0 μM, respectively), Δ 9 -tetrahydrocannabinol ( Δ 9 -THC ) and Δ 8 -THC (EC 50 s = 1.6 and 2.0 μM, respectively), and the artificial CB 1 R agonist, CP55,940 ( CP , EC 50 = 82 nM); however their potencies were less than what has been described at CB 1 R. Cannabidiol ( CBD ) did not affect basal GRAB eCB2.0 fluorescent signal and yet reduced the 2-AG stimulated GRAB eCB2.0 responses (IC 50 = 8.8 nM). Conclusions 2-AG and SR1 modulate the GRAB eCB2.0 fluorescent signal with EC 50 s that mirror their potencies at CB 1 R whereas AEA, eCB analogues, THC and CP increase GRAB eCB2.0 fluorescent signal with EC 50 s significantly lower than their potencies at CB 1 R. CBD reduces the 2-AG response without affecting basal signal, suggesting that GRAB eCB2.0 retains the negative allosteric modulator ( NAM ) property of CBD at CB 1 R. This study describes the pharmacological profile of GRAB eCB2.0 to improve interpretation of changes in fluorescent signal in response to a series of known eCBs and CB 1 R ligands.","journal":"bioRxiv (Cold Spring Harbor Laboratory)","year":2023,"id":394274,"datarank":0.20794415416798362,"base_score":1.3862943611198906,"endowment":1.3862943611198906,"self_citation_contribution":0.20794415416798362,"citation_network_contribution":0.0,"self_endowment_contribution":0.20794415416798362,"citer_contribution":0.0,"corpus_percentile":null,"corpus_rank":null,"citation_count":3,"citer_count":0,"citers_with_citation_signal":0,"citers_with_endowment":0,"datacite_reuse_total":0,"is_dataset":false,"is_dataset_confidence":0.9584,"is_data_producer":false,"deposit_databanks":null,"is_oa":true,"file_count":0,"downloads":0,"has_version_chain":false,"published_date":"2023-01-01","fair_score":null,"fair_percentile":null,"algorithm_id":"datarank_citation_only_1hop_v6","ranking_scope":"data_only","authors":[{"id":987731,"name":"Dennis Sarroza","orcid":null,"position":1,"is_corresponding":false},{"id":987249,"name":"Anthony English","orcid":"0000-0003-4490-8654","position":2,"is_corresponding":false},{"id":1082158,"name":"Maya McGrory","orcid":null,"position":3,"is_corresponding":false},{"id":571610,"name":"Ao Dong","orcid":"0000-0002-2821-9528","position":4,"is_corresponding":false},{"id":262515,"name":"Larry S. Zweifel","orcid":"0000-0003-3465-5331","position":5,"is_corresponding":false},{"id":370030,"name":"Benjamin B. Land","orcid":"0009-0007-4725-7929","position":6,"is_corresponding":false},{"id":151125,"name":"Yulong Li","orcid":"0000-0002-9166-9919","position":7,"is_corresponding":false},{"id":303878,"name":"Michael R. Bruchas","orcid":"0000-0003-4713-7816","position":8,"is_corresponding":false},{"id":507119,"name":"Nephi Stella","orcid":"0000-0002-4780-8360","position":9,"is_corresponding":false},{"id":987248,"name":"Simar Singh","orcid":"0000-0001-5785-8292","position":0,"is_corresponding":true}],"reference_count":53,"raw_metadata":{"citation_network_status":"fetched"},"created_at":"2026-07-19T01:19:10.334330Z","pmid":"36945533","pmcid":null,"fwci":null,"citation_percentile":null,"influential_citations":0,"oa_status":null,"license":null,"views":0,"total_file_size_bytes":0,"version_count":0,"fair_f":null,"fair_a":null,"fair_i":null,"fair_r":null,"fair_zscore":null,"fair_rationale":null,"fair_model":null,"fair_agent_version":null,"fair_fulltext_source":null,"fair_has_llm":null,"fair_computed_at":null,"clinical_trials":[],"software_tools":[],"db_accessions":[],"linked_datasets":[],"topics":[]}