Table 2.

Examples of the cross-talk between the (endo)cannabinoid and renin-angiotensin systems.

Species	Model	Agonist Concentration (μM) or Dose	Effect	(Functional) Antagonist; Concentration In Vitro (μM) or Dose	Influence on the Agonist Effect	Final Conclusion of the Authors	References
cells: Chinese hamster; human; African green monkey	CHO; HEK293; COS7 cells (co-expressing AT1Rs and CB1Rs) from ovaries, kidneys, and fibroblasts, respectively	Ang II (0.1)	↑2-AG ↔AEA ↑Go protein activation	AM251 (10) THL (1)	↓Ang II-induced Go protein activation	AT1R stimulation leads to DAGL-mediated transactivation of CB1Rs in an autocrine and paracrine manner	[33,34]
cells : mouse	neuro2A cells, a neuroblastoma cell line co-expressing CB1Rs and AT1Rs	Ang II (0.01–10)	↑pERK levels via Gαi instead of Gαq the expression of AT1R shifts CB1Rs from an intracellular compartment to the plasma membrane	losartan CB1R-targeting siRNA RIM (1) THL (1) HU210 (0.0001)	Ang II-induced ↑pERK ↓ by losartan, CB1R-targeting siRNA, RIM, and THL; ↑ by HU210 (occurring in the presence of a very low non-signaling concentration of Ang II only)	AT1Rs and CB1Rs form receptor heteromers; blocking CB1R activity prevented the Ang II-mediated pathologic effect	[35]
cells : rats	hepatic stellate cells from control rats (cHSCs) and rats treated with ethanol for 8 months (eHSCs)	Ang II (1)	CB1R, AT1R and AT1R-CB1 heteromer levels in eHSCs > cHSCs; ↑pERK levels, ↑mitogenic and ↑profibrogenic markers in eHSCs > cHSCs	RIM (1)	↓Ang II-induced changes
Blood Vessels
rats Wistar	aortic VSMCs	Ang II (0.1)	↑2-AG level ↑Ca2+ signal	THL (1) JZL184 (1)	↓ and ↑ of Ang II-induced 2-AG formation and Ca2+ signal by THL and JZL184, respectively	Ang II stimulates eCB (2-AG) release from the vascular wall that reduces the vasoconstrictor effects of Ang II via CB1R activation (eCBs act as protective negative feedback in response to Ang II)	[36]
rats and/or mice	aortic rings from rats aortic rings from CB1−/− and WT mice	Ang II (0.001–0.1)	concentration-dependent contraction	WIN-2 (10) O2050 (1) THL (1) JZL184 (1)	vasodilation to WIN-2; not detected in CB1−/− O2050, THL↑ , and JZL184↓ vasoconstrictor effect of Ang II; amplificatory effect of O2050 in WT only
rats and/or mice	skeletal muscle arterioles, saphenous arteries	Ang II (0.001–0.1)	concentration-dependent contraction	WIN-2 (1) O2050 (1) RIM (1) AM251 (1) THL (1)	vasodilation to WIN-2; not detected in CB1−/− ↑vasoconstrictor effect of Ang II in WT but not in CB1−/−	Ang II stimulates eCB release from the vascular wall that reduces the vasoconstrictor effects of Ang II via CB1R activation (eCBs act as protective negative feedback in response to Ang II)	[37]
rats Wistar	intramural coronary resistance arterioles	Ang II (0.0001–10)	concentration-dependent contraction	WIN-2 (0.0001–1) O2050 (1) THL (1)	vasodilatation to WIN-2 reduced by O2050 and AM251 ↑vasoconstrictor effect of Ang II	Ang II stimulates eCB release from the vascular wall that reduces the vasoconstrictor effects of Ang II via CB1R activation (eCBs act as protective negative feedback in response to Ang II)	[38]
rats Wistar	pulmonary arteries	Ang II (0.0001–0.03)	concentration-dependent contraction	AM251 (1) RHC80267 (40) JZL184 (1) URB597 (1)	AM251 and RHC80267 ↑ but JZL184 ↓ vasoconstrictor effect of Ang II; URB597 ↔	Ang II stimulates eCB (2-AG) release from the vascular wall that reduces the vasoconstrictor effects of Ang II via CB1R activation (eCBs act as protective negative feedback in response to Ang II)	[39]
rats	uterine artery from hypertensive TgA and normotensive SD rats	Ang II (0.00001–0.01)	concentration-dependent contraction, stronger in TgA	URB597 (1) JZL184 (1) RIM (1)	↓responses to Ang II in SD and TgA ↓responses to Ang II in TgA ↔responses to Ang II in SD and TgA	eCBs reduce the Ang II-induced contraction in a CB1R-independent manner in the early stages of hypertensive pregnancy (eCBs act as protective negative feedback in response to Ang II)	[40]
rats SD mice	VSMCs from rat and mouse thoracic aortas with CB1R expression	Ang II (1)	↑ROS production ↑NADPH oxidase activity	RIM (0.1–1) or AM251 (1) CP55940 (1)	↓AT1Rs and decrease in the Ang II-induced ↑ROS production and ↑NADPH oxidase activity ↑AT1Rs	CB1R inhibition (in vitro and in vivo) has atheroprotective effects by down-regulation of AT1Rs, decreased vascular ROS, and thus improved endothelial function in hypercholesterolemic ApoE−/− mice	[41]
mice	ApoE−/− treated with a cholesterol-rich diet		development of atherosclerotic plaques, ↓aorta relaxation, ↔aortic AT1R level	RIM (10 mg/kg/day; p.o.) for 7 weeks	↓aortic AT1Rs and improvement of endothelial function, no effect on atherosclerotic plaques
Heart
rats SD	isolated Langendorff-perfused hearts	Ang II (0.001–0.1) 2-AG (1) WIN-2 (1)	↓CF and moderate negative inotropic effect 2-AG and WIN-2: ↑CF WIN-2: negative inotropic effect	O2050 (1) + Ang II orlistat (10) + Ang II	↓cardiac effects of Ang II	besides direct cardiac responses, Ang II induces indirect ones via eCBs (probably 2-AG) activating CB1Rs: -direct positive inotropy reversed into a negative one, ↓oxygen demand -direct coronary constriction attenuated, (↑)oxygen supply (eCBs act as protective negative feedback in response to Ang II)	[42]
mice	streptozotocin-induced diabetes	diabetic cardiomyopathy	↑myocardial CB1 and AT1R expression and AEA level connected with cardiac dysfunction, inflammation, oxidative/nitrative stress	RIM or AM281 (10 mg/kg; i.p. daily for 11 weeks) or CB1R deletion (CB1−/− mice)	pharmacological inhibition or genetic deletion of CB1Rs—improvement of diabetic cardiac dysfunction connected with ↓AT1Rs and CB1Rs in LV	overactivation of the eCB system and CB1Rs may play an important role in the pathogenesis of diabetic cardiomyopathy by facilitating AT1R expression and signaling	[43]
rats Wistar	isolated Langendorff-perfused hearts underwent ischemia + reperfusion	ischemia and reperfusion	↑stroke size, ↓ventricular function; ↑ cardiac AT1R level and ↔ cardiac AT2R level	CBD (5 mg/kg; i.p. daily for 10 days)	↓stroke size and ↑ventricular function; ↓ cardiac AT1R level and ↑ cardiac AT2R level	cardioprotective effect of CBD might result from an increase in cardioprotective AT2Rs stimulating counter-regulatory effects on the AT1Rs	[44]
mice	Ang II-induced fibrosis and inflammation	Ang II infusion (1 µg/kg/min [preventive] or 500 [therapeutic] for 4 weeks)	fibrosis and inflammation in the heart, aorta, lung, kidney, and skin	EHP-101 (2, 5 or 20 mg/kg for 4 or 2 weeks)	↓cardiac, aortic, lung, kidney, and skin fibrosis and inflammation in the preventive or therapeutic model	EHP-101 (dual agonist of CB2Rs and PPARγ) can alleviate cardiac, aortic, lung, kidney, and skin inflammation induced by Ang II	[45]
Blood Pressure
mice CB1−/− CB1+/+	anesthetized	Ang II (1 μg/kg/min)	↑BP in WT and CB1−/−	O2050 (10 mg/kg; p.o.)	↑ pressor effect of Ang II in WT, not in CB1−/−	confirmation of in vitro experiments on isolated arteries that Ang II stimulates release of eCBs (2-AG) from the vascular wall that reduce vasoconstrictor effects of Ang II via CB1R activation	[36]
rats SD	conscious	Ang II-induced hypertension (60 ng/min; s.c. for 10–12 days)	↑BP	AM251 (3 mg/kg; i.v.) URB597 (10 mg/kg; i.v.) in pentobarbital- anaesthetized rats	AM251 ↑BP and URB597 ↓BP in Ang II-induced hypertension but not in normotension	the Ang II-induced hypertension is diminished by eCBs acting at CB1Rs; effect of URB597 reduced by AM251	[19]
rats Wistar	conscious	Ang II (500 ng/kg/h) + VP (50 ng/kg/h for 4 days)- induced hypertension	↑BP	AEA (3 mg/kg) URB597 (3 mg/kg) WIN-2 (150 μg/kg) AM251 (3 mg/kg)	AEA, WIN-2 ↓BP in Ang II-VP-induced hypertension; URB597 enhanced the effect of AEA; AM251 blocked the effect of WIN-2	the Ang II-VP induced hypertension might be diminished by eCBs acting at CB1Rs	[46]
rats SHR WKY	conscious		BP was higher in SHR than in WKY	RIM 3 mg/kg i.v. URB597 1.7 mg/kg i.v.	RIM ↑BP and URB597 ↓BP in SHR but not in normotensive WKY	in SHR in which RAS is overactivated eCBs acting at CB1Rs reduce BP	[19]
rats	conscious (mRen2)27 hypertensive rats or normotensive SD	(mRen2)27: higher RAS activity		RIM (10 mg/kg; p.o. acutely or daily for 28 days)	acutely: ↓BP and ↓HR in hypertensive but not in SD chronically: ↓BP and ↓HR; ↔plasma Ang II, ↔Ang 1-7; ↔ACE; improvement of sympathetic and parasympathetic BRS	upregulated ECS contributes to hypertension and impaired autonomic function in this Ang II-dependent model; systemic CB1R blockade may be an effective therapy for Ang II-dependent hypertension and the associated metabolic syndrome	[47]
rats	anaesthetized (mRen2)27 hypertensive, ASrAOGEN and SD rats	(mRen2)27: higher RAS activity; AsrAO-GEN: low glial angiotensinogen	levels in NTS: 2-AG: (mRen2)27 > SD > ASrAOGEN; AEA: (mRen2)27 ≈ SD ≈ ASrAOGEN dorsal medulla: CB1: ASrAOGEN < (mRen2)27 ≈ SD; CB2: no differences	RIM (0.36 and 36 pmol/rat; NTS)	↑BRS in (mRen2)27; ↓BRS in ASrAOGEN; ↔BRS in SD	upregulated brain ECS in Ang II-dependent hypertension may contribute to the impaired baroreceptor sensitivity in this model of hypertension	[48]
rats	obese fa/fa Zucker rats and control lean fa/+ Zucker rats; isoflurane-anaesthetized	acute Ang II (30 and 100 ng/kg, i.v.)	stronger pressor response in obese than in lean rats	RIM (3 or 10 mg/kg, p.o.) for 12 months	normalized the acute pressor response to Ang II in obese rats to the level of lean rats	authors suggest that chronic CB1R blockade by RIM might reduce vascular AT1R expression; an indirect mechanism related to the decrease in the cholesterol level should also be taken under consideration	[49]
rats SHR WKY	conscious		SHR in comparison to WKY: higher BP, carotid, mesenteric artery: ↑AT1Rs, ↑ACE kidney: ↔AT1Rs, ↔AT2Rs, ↑ACE	PEA (30 mg/kg; s.c. for 5 weeks)	BP in SHR↓ SHRarteries: ↓AT1Rs, ↓ACE level SHR kidney: ↓AT1Rs, ↑AT2Rs, and ↓ACE level associated with ↓oxidative and nitrosative stress	PEA lowers BP and protects against hypertensive renal injury partially via reduction in vascular AT1Rs and Ang II-mediated effects and via modulation of the RAS, leading the AT1/AT2 balance towards an anti-hypertensive status	[50,51]
rats WKY	cultured lymphocytes from WKY	Ang II (0.01–1)	concentration-dependent ↓AEA transporter activity and ↑ROS level	losartan (10 and 100)	↓Ang II effects on AEA transporter activity and ROS level	Ang II plays a critical role in mediating the decrease in AEA transporter activity in SHR; probably via AT1Rs	[52]
rats SHR WKY	conscious		SHR: ↑plasma Ang II and ↑AEA level; ↓AEA transporter activity in comparison to WKY	losartan (15 or 30 mg/kg; p.o. for 2 weeks)	restoration of reduced AEA transporter activity; ↓plasma AEA level
Nervous System
rats Wistar	urethane- anesthetized	Ang II (0.14 nmol/rat; PVN)	↑BP	AM251 (0.48 nmol/rat; PVN)	AM251 reduced the Ang II-mediated BP increase and slightly increased BP by itself	Ang II-induced hypertension involves CB1Rs in the PVN	[53]
rats Wistar	urethane- anaesthetised (microinjection into the PVN, doses in nmol/rat)	CP55940 (0.1) CP55940 (0.1) + AM251 (3 μmol/kg; i.v.)	↓BP, ↓HR ↑BP, ↑HR	losartan (10 μmol/kg; i.v.) losartan (10 μmol/kg; i.v.)	no effect reversed ↑BP, ↑HR to ↓BP, ↓HR	presynaptic inhibitory CB1Rs on GABAergic neurons in the PVN activated by eCBs released in response to Ang II modify the glutamatergic neurotransmission enhanced by presynaptic AT1R activation	[54]
rats SHR WKY	conscious (all compounds microinjected into the PVN, nmol/rat)	Ang II (0.03) or CP55940 (0.1) + AM251 (3 μmol/kg; i.v.)	↑BP stronger in SHR than in WKY	losartan (20) PD123319 (10) AM251 (30)	↓pressor effect of Ang II and CP55940 ↓pressor effect of Ang II and CP55940 ↓pressor effect of Ang II	mutual interaction in the PVN between CB1Rs and receptors for Ang II responsible for stimulation of the pressor response (probably via stimulation of CB1R by eCBs released in response to Ang II)	[55]
mice	magnocellular neurosecretory cells from the supraoptic nucleus	Ang II (0.1)	↑frequency of mEPSCs	AM251 (2)	↑effect of Ang II	eCBs released in response to Ang II modulate the excitatory synaptic inputs via negative feedback	[56]
rats Wistar mice CB1+/+ CB1−/−	conscious	Ang II (191 pmol/rat; i.c.v.) Ang II (191 pmol/mouse i.c.v.)	↓ethanol-induced gastric lesions (reduced by candesartan 5.2 and 31.7 nmol/rat; i.c.v.) gastroprotection in CB1+/+ as opposed to CB1−/−	AM251 (1.8 nmol/rat; i.c.v.) THL (0.2 nmol/rat; i.c.v.)	inhibition of the gastroprotective effect of Ang II	Ang II stimulates eCB release via activation of central AT1R receptors, and activation of CB1Rs induces gastroprotection in a vagus-mediated mechanism (inhibition by vagotomy and atropine)	[57]
mice CB1+/+ CB1−/	response of the chorda tympani (CT) nerve in anesthetized mice	CB1+/+: Ang II (100–5000 ng/kg; i.p.)	gustatory nerve responses ↓ to NaCl and ↑ to sweeteners, blocked by candesartan	CB1–/–: Ang II (100–5000 ng/kg; i.p.)	gustatory nerve responses ↓ to NaCl and ↔ to sweeteners	enhancing effect of Ang II on sweet taste responses mediated by AT1 and CB1Rs; authors suggest that Ang II, via AT1Rs, stimulates the release of 2-AG that may act as an autocrine enhancer for CB1Rs on sweet taste cells	[58]
rats SHR WKY	astrocytes  basal CB1R densities: brainstem: SHR<WKY cerebellum: SHR>WKY	Ang II (0.1)	SHR: ↓CB1R and ↑CB1R densities and phosphorylation in brainstem and cerebellar astrocytes, respectively; opposite effects in WKY	losartan (10) PD123319 (10) ACEA (0.01)	- effects of Ang II were inhibited by losartan (brainstem) and by losartan and PD123319 (cerebellum) - ACEA reduced the AT1R-mediated MAPK activation in brainstem and cerebellar astrocytes	Ang II, mostly via the AT1R, is capable of altering CB1R expression and phosphorylation in astrocytes isolated from the brainstem and cerebellum under hyper- and normotensive conditions; possible role in neuroinflammatory and attention-deficit hyperactivity disorders, respectively	[59,60]
rats SHR WKY	astrocytes isolated from the brainstem and from cerebellum	Ang II (0.1)	↓IL-10 and ↑IL-1β gene expression in astrocytes from both brain regions of SHR and WKY	ACEA (0.01)	co-treatment of Ang II and ACEA resulted in the neutralization of Ang II-mediated effect in WKY but not SHR	Ang II and ACEA have opposing roles in the regulation of inflammatory gene signature in astrocytes isolated from SHR and Wistar rats (possible functional antagonism)	[61]
mice CB2−/− CB2+/+	hippocampus slices		CB2−/−: ↓ACE level, and ↑aβP in comparison to WT		CB2R deletion:↑aβ neurotoxicity associated with ↓level of ACE (that degrades aβ)	activation of CB2Rs increases ACE level that degrades aβ; possible significance in Alzheimer’s disease	[62]
	N2a cells overexpressing aβP	JWH133	↑ACE level, ↓aβP	AM630	all JWH133 effects were attenuated
Kidney
humans	podocytes	Ang II (0.1)	↑AEA, ↑2-AG ↑AT1Rs and CB1Rs	JD5037 (100) or losartan (10)	↓ all changes induced by Ang II	peripheral CB1R blockade might possess therapeutic potential in disease(s) connected with enhanced RAS	[63]
rats	Zucker diabetic fatty rats with nephropathy; control lean rats	diabetic compared to lean rats	↑plasma Ang II and aldosterone levels; ↓AT1Rs in renal cortex	JD5037 (3 mg/kg p.o. for 3 months) losartan (20 mg/kg p.o. for 28 days)	↓plasma Ang II and aldosterone levels; ↓AT1Rs in renal cortex ↔plasma Ang II and ↓aldosterone levels; ↓CB1Rs in renal cortex
mice	streptozotocin- induced diabetic nephropathy		↑glomerular CB1 and ↑AT1Rs; ↔CB2Rs	AM6545 (10 mg/kg; i.p.) alone or together with perindopril (2 mg/kg; p.o.) for 14 weeks	Single treatments ↔glomerular CB1-, CB2Rs, and ↓AT1Rs; ↓progression of albuminuria, down-regulation of nephrin and podocin, ↓inflammation, and ↓expression of markers of fibrosis Combinedtreatment ↔glomerular CB1-, CB2Rs and ↓AT1Rs; also reversal of albuminuria	The superior effect of dual therapy (peripheral CB1R antagonist + ACE inhibitor) on albuminuria, nephrin loss, and inflammation suggest that CB1R blockade may be a valuable option as an additional therapy, although single and combined treatment only reduce glomerular AT1Rs without affecting CB1Rs and CB2Rs.	[64]

↓—decrease; ↑—increase; ↔—no change. 2-AG, 2-arachidonoyl glycerol; A549, alveolar epithelial cell line; AβP, amyloid-β protein; ACE, angiotensin-converting enzyme; ACE2, angiotensin-converting enzyme 2; ACEA, arachidonyl-2’-chloroethylamide; AEA, anandamide; Ang II, angiotensin II; Ang 1-7, angiotensin 1-7; ApoE, apolipoprotein E; ASrAOGEN, transgenic rats characterized by a transgene producing antisense RNA against angiotensinogen in the brain; AT₁R, Ang II receptor type 1; AT₂R, Ang II receptor type 2; BRS, baroreceptor sensitivity; CB₁R, cannabinoid receptor type 1; CB₂R, cannabinoid receptor type 2; CBD, cannabidiol; CBG, cannabigerol; CBN, cannabinol; CF, coronary flow; CHO, Chinese hamster ovary cells; DAGL, diacylglycerol lipase; eCBs, endocannabinoids; ECS, endocannabinoid system; EHP-101 (VCE-004.8), oral lipidic formulation of the novel non-psychotropic cannabidiol aminoquinone; ERK, extracellular signal-regulated kinases; FAAH, fatty acid amide hydrolase; hACE2, human ACE2; hiPSC-CMs, human iPSC-derived cardiomyocytes; HSC, hepatic stellate cells; IFN-γ, interferon γ; i.c.v., intracerebroventricular; IL-1β, interleukin-1β; IL-10, interleukin-10; i.p., intraperitoneal; i.v., intravenous; HR, heart rate; LDH, lactate dehydrogenase; LV, left ventricle; MAGL, monoacylglycerol lipase; MAPK, mitogen-activated protein kinase; mEPSCs, miniature excitatory postsynaptic currents; (mRen2)27, Ang II-dependent hypertension model; NA, noradrenaline; NTS, solitary tract nucleus; PEA, N-palmitoylethanolamide; pERK, phospho-ERK; p.o., per os; PVN, paraventricular nucleus of hypothalamus; RIM, rimonabant; RAS, renin angiotensin system; ROS, reactive oxygen species; s.c., subcutaneous; SD, Sprague-Dawley rats; SHR, spontaneously hypertensive rat; TgA, transgenic rat, model of preeclampsia; THC, Δ⁹-tetrahydrocannabinol; THCV, tetrahydrocannabivarin; THL, tetrahydrolipstatin; TMPRSS2, transmembrane serine protease 2; TNF-α, tumor necrosis factor α; URB597, an inhibitor of FAAH (fatty acid amide hydrolase); WIN-2, WIN55212-2; WKY, Wistar Kyoto rats; WT, wild type; VSMCs, vascular smooth muscle cells; VP, vasopressin.