Visualization of 2‐arachidonoylglycerol accumulation and cannabinoid CB 1 receptor activity in rat brain cryosections by functional autoradiography
| Autor: | Juha R. Savinainen, Marko Lehtonen, Jarmo T. Laitinen, Ville A. B. Palomäki |
|---|---|
| Rok vydání: | 2006 |
| Předmět: |
Male
Cannabinoid receptor Diacylglycerol lipase medicine.medical_treatment 2-Arachidonoylglycerol Organophosphonates Arachidonic Acids Binding Competitive Biochemistry Glycerides Cellular and Molecular Neuroscience chemistry.chemical_compound Piperidines Receptor Cannabinoid CB1 medicine Animals Drug Interactions Sulfones Enzyme Inhibitors Rats Wistar Receptor biology Chemistry Brain URB597 Endocannabinoid system Rats Rhc80267 Radiography Guanosine 5'-O-(3-Thiotriphosphate) Benzamides biology.protein Autoradiography Pyrazoles lipids (amino acids peptides and proteins) Carbamates Cannabinoid Cryoultramicrotomy Endocannabinoids |
| Zdroj: | Journal of Neurochemistry. 101:972-981 |
| ISSN: | 1471-4159 0022-3042 |
| Popis: | In neuronal signalling mediated by the endocannabinoid 2-arachidonoylglycerol, both synthetic and inactivating enzymes operate within close proximity to the G(i/o)-coupled pre-synaptic CB(1) receptors, thus allowing for rapid onset and transient duration of this lipid modulator. In rat brain, 2-arachidonoylglycerol is inactivated mainly via hydrolysis by serine hydrolase inhibitor-sensitive monoacylglycerol lipase activity. We show in this study that comprehensive pharmacological elimination of this activity in brain cryosections by methyl arachidonylfluorophosphonate or hexadecylsulphonyl fluoride results in endocannabinoid-mediated CB(1) receptor activity, which can be visualized by functional autoradiography. URB597, a specific inhibitor of anandamide hydrolysis proved ineffective. TLC indicated that the bioactivity resided in 2-arachidonoylglycerol-containing fraction and gas chromatography-mass spectroscopy detected elevated levels of monoacylglycerols, including 2-arachidonoylglycerol in this fraction. Although two diacylglycerol lipase inhibitors, tetrahydrolipstatin (THL) and RHC80267, blocked the bulk of 2-arachidonoylglycerol accumulation in methyl arachidonylfluorophosphonate-treated sections, only THL reversed the endocannabinoid-dependent CB(1) receptor activity. Further studies indicated that at the used concentrations, THL rather specifically antagonized the CB(1) receptor. These findings confirm that in brain sections there is preservation of enzymatic pathways regulating the production of endogenous receptor ligands. Furthermore, the presently described methodology may serve as an elegant and intuitive approach to identify novel membrane-derived lipid modulators operating in the CNS. |
| Databáze: | OpenAIRE |
| Externí odkaz: |
|
Plný text