The effects of beta-arrestin1 deletion on acute cannabinoid activity, brain cannabinoid receptors and tolerance to cannabinoids in mice
The effects of beta-arrestin1 deletion on acute cannabinoid activity, brain cannabinoid receptors and tolerance to cannabinoids in mice
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DOI:
10.3109/10799893.2014.1003659
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发表时间:
2015-02-01
影响因子:
2.8
通讯作者:
Vaghela, Manan S.
中科院分区:
文献类型:
--
作者:
Breivogel, Chris S.;Vaghela, Manan S.
Context: Previous studies have indicated a role for beta-arrestin2 in the regulation of brain cannabinoid effects and cannabinoid CB1 receptors, but whether beta-arrestin1 has a role has not been investigated. Objective: To determine the role of beta-arrestin1 in cannabinoid activity. Materials and methods: Beta-arrestin1 -/- mice and their wild-type (+/+) counterparts were assayed for antinociceptive and temperature-decreasing effects of two ligands, Delta(9) -tetrahydro-cannabinol (THC) and CP55940, after both single and repeated administration. In vitro assays examined the effects of deletion on CB1 receptor density, agonist-binding and G-protein activation. Results: Deletion of beta-arrestin1 diminished the effects of CP55940 in both antinociception (latency to tail withdrawal) and temperature-depression assays in mice. However, deleting beta-arrestin1 had no effect on the actions of THC in either assay. Antagonist radioligand ([H-3]SR141716A) saturation binding indicated no difference between beta-arrestin1 +/+ and -/- mice in the density or affinity for cannabinoid CB1 receptors in brain membranes. CP55940 agonist binding in brain membranes from beta-arrestin1 +/+ mice exhibited high-and intermediate-affinity sites, but beta-arrestin1 -/- membranes exhibited an additional site with low affinity. CP55940 produced greater stimulation of [S-35] GTP gamma S binding to membranes from whole brain of beta-arrestin1 -/- than +/+ mice. The rates of the development of tolerance to chronic THC or CP55940 administration did not appear to be affected by genotype. Discussion: Beta-arrestin1 appeared to mediate the actions of CP55940, but did not affect the activity of THC. Conclusion: Beta-arrestin1 regulates cannabinoid CB1 receptor sensitivity in an agonist-selective manner, but may not be the primary mediator of tolerance to cannabinoid agonists.