glyceryl-2-arachidonate and Hypertension

The interaction between the endocannabinoid and ROS signaling systems has been demonstrated in different organs. Inhibitors of fatty acid amide hydrolase (FAAH), the key enzyme responsible for degradation of the endocannabinoid anandamide, are postulated to possess anti-hypertensive potential. Here, we compared the effects of hypertension and chronic FAAH inhibition by URB597 on the endocannabinoid system and redox balance in spontaneously hypertensive rats (SHR) and hypertensive deoxycorticosterone acetate (DOCA)-salt rats. Enhanced oxidative stress and lipid peroxidation were found in both hypertension models. Hypertension affected cardiac and plasma endocannabinoid systems in a model-dependent manner: anandamide and 2-arachidonoylglycerol levels decreased in SHR and increased in DOCA-salt. Cardiac CB

Topics: Amidohydrolases; Animals; Arachidonic Acids; Benzamides; Carbamates; Desoxycorticosterone Acetate; Endocannabinoids; Glycerides; Heart; Hypertension; Male; Myocardium; Oxidation-Reduction; Oxidative Stress; Polyunsaturated Alkamides; Rats, Inbred SHR; Rats, Wistar; Receptor, Cannabinoid, CB1; Receptor, Cannabinoid, CB2

Activation of G protein-coupled receptors (GPCRs) can induce vasoconstriction via calcium signal-mediated and Rho-dependent pathways. Earlier reports have shown that diacylglycerol produced during calcium signal generation can be converted to an endocannabinoid, 2-arachidonoylglycerol (2-AG). Our aim was to provide evidence that GPCR signaling-induced 2-AG production and activation of vascular type1 cannabinoid receptors (CB1R) is capable of reducing agonist-induced vasoconstriction and hypertension. Rat and mouse aortic rings were examined by myography. Vascular expression of CB1R was demonstrated with immunohistochemistry. Rat aortic vascular smooth muscle cells (VSMCs) were cultured for calcium measurements and 2-AG-determination. Inhibition or genetic loss of CB1Rs enhanced vasoconstriction induced by angiotensin II (AngII) or phenylephrine (Phe), but not by prostaglandin(PG)F2α. AngII-induced vasoconstriction was augmented by inhibition of diacylglycerol lipase (tetrahydrolipstatin) and was attenuated by inhibition of monoacylglycerol lipase (JZL184) suggesting a functionally relevant role for endogenously produced 2-AG. In Gαq/11-deficient mice vasoconstriction was absent to AngII or Phe, which activate Gq/11-coupled receptors, but was maintained in response to PGF2α. In VSMCs, AngII-stimulated 2-AG-formation was inhibited by tetrahydrolipstatin and potentiated by JZL184. CB1R inhibition increased the sustained phase of AngII-induced calcium signal. Pharmacological or genetic loss of CB1R function augmented AngII-induced blood pressure rise in mice. These data demonstrate that vasoconstrictor effect of GPCR agonists is attenuated via Gq/11-mediated vascular endocannabinoid formation. Agonist-induced endocannabinoid-mediated CB1R activation is a significant physiological modulator of vascular tone. Thus, the selective modulation of GPCR signaling-induced endocannabinoid release has a therapeutic potential in case of increased vascular tone and hypertension.

Topics: Angiotensin II; Animals; Aorta; Arachidonic Acids; Benzodioxoles; Calcium; Calcium Signaling; Dinoprost; Endocannabinoids; Gene Expression Regulation; Glycerides; GTP-Binding Protein alpha Subunits, Gq-G11; Hypertension; Lactones; Lipoprotein Lipase; Male; Mice; Mice, Knockout; Monoacylglycerol Lipases; Muscle, Smooth, Vascular; Myocytes, Smooth Muscle; Orlistat; Phenylephrine; Piperidines; Rats; Rats, Wistar; Receptor, Cannabinoid, CB1; Tissue Culture Techniques; Vasoconstriction