The nonpsychoactive cannabinoid abnormal‐cannabidiol (trans‐4‐3‐methyl‐6‐(1‐methylethenyl)‐2‐cyclohexen‐1‐yl‐5‐pentyl‐1,3‐benzenediol) (abn‐cbd) produced concentration‐dependent relaxation of ...methoxamine‐precontracted rat small mesenteric artery. Endothelial removal reduced abn‐cbd potency six‐fold without affecting the maximum relaxation.
In endothelium‐intact vessels, abn‐cbd was less potent under 60 mM KCl‐induced tone and inhibited by combination of L‐NG‐nitroarginine methyl ester (L‐NAME) (nitric oxide synthase inhibitor; 300 μM), apamin (small conductance Ca2+‐activated K+ channels inhibitor; 50 nM) and charybdotoxin (inhibitor of intermediate conductance Ca2+‐activated K+ channels and large conductance Ca2+‐activated K+ channels BKCa; 50 nM). L‐NAME alone or in combination with either toxin alone had little effect.
In intact vessels, relaxations to abn‐cbd were inhibited by SR 141716A (cannabinoid receptor antagonist; 1 or 3 μM). Concomitant addition of L‐NAME, apamin and charybdotoxin had no further effect. Other cannabinoid receptor antagonists either had little (SR 144528; 1 μM and AM 251; 1 μM) or no effect (AM 630; 10 μM and AM 281; 1 μM). Inhibition of gap junctions, Gi/o protein coupling and protein kinase A also had no effect.
Endothelium‐independent relaxation to abn‐cbd was unaffected by L‐NAME, apamin plus charybdotoxin or capsaicin (10 μM). Abn‐cbd inhibited CaCl2‐induced contractions in vessels with depleted intracellular Ca2+ stores and stimulated with methoxamine or KCl. This was insensitive to SR 141716A (3 μM) but greatly reduced in vessels stimulated with ionomycin (Ca2+ ionophore; 1 μM).
We conclude that abn‐cbd relaxes the rat small mesenteric artery by endothelium‐dependent activation of K+ channels via SR 141716A‐sensitive pathways, which do not involve CB1 and CB2 receptors. It also causes endothelium‐independent, SR 141716A‐insensitive, relaxation by inhibiting Ca2+ entry through voltage‐gated Ca2+ channels.
British Journal of Pharmacology (2003) 138, 1320–1332. doi:10.1038/sj.bjp.0705160
Three cannabinoid receptor agonists, anandamide (CB1 receptor‐selective) and the aminoalkyl‐indoles, JWH 015(2‐methyl‐1‐propyl‐1H‐indol‐3‐yl)‐1‐napthalenylmethanone; (CB2 receptor‐selective), ...R‐(+)‐WIN 55,212‐2 (R‐(+)‐2,3‐dihydro‐5‐methyl‐3‐(4‐morpholinylmethyl)pyrrolol1,2,3‐de‐1,4‐benzoxazin‐6‐yl‐1‐napthalenylmethanone; slightly CB2 receptor‐selective), as well as the enantiomer S‐(−)‐WIN 55,212‐3(S‐(−)‐2,3‐dihydro‐5‐methyl‐3‐(4‐morpholinylmethyl)pyrrolol1,2,3‐de‐1,4‐benzoxazin‐6‐yl‐1‐napthalenylmethanone; inactive at cannabinoid receptors), induced endothelium‐independent relaxation of methoxamine‐precontracted isolated small mesenteric artery of rat. KCL (60 mM) precontraction did not affect relaxation to the aminoalkylindoles, but reduced that to anandamide.
SR14176A (N‐(piperidin‐1‐yl)‐5‐(4‐chlorophenyl)‐1‐(2,4‐dichlorophenyl)‐4‐methyl‐1H‐pyrazole‐3‐carboxamide; 3 μM; CB1 receptor antagonist) inhibited relaxation only to JWH 015 and anandamide. Neither AM 251 (N‐(piperidin‐1‐yl)‐5‐(4‐iodophenyl)‐1‐(2,4‐dichlorophenyl)‐4‐methyl‐1H‐pyrazole‐3‐carboxamide; CB1 antagonist) nor SR 144528 (N‐(1S)‐endo‐1,3,3‐trimethyl bicyclo2.2.1 heptan‐2‐yl‐5‐(4‐chloro‐3‐methylphenyl)‐1‐(4‐methylbenzyl)‐pyrazole‐3‐carboxamide; CB2 antagonist; both at 3 μM) affected any of the relaxations.
Vanilloid receptor desensitisation with capsaicin reduced anandamide relaxation; addition of SR 141716A (3 μM) then caused further inhibition. SR 141716A did not affect capsaicin‐induced relaxation.
The aminoalkylindoles inhibited CaCl2‐induced contractions in methoxamine‐stimulated vessels previously depleted of intracellular Ca2+. These inhibitory effects were greatly reduced or abolished in ionomycin‐(a calcium ionophore) contracted vessels. Anandamide also caused vanilloid receptor‐independent, SR 141716A‐ (3 μM) insensitive, inhibition of CaCl2 contractions.
In conclusion, the aminoalkylindoles JWH 015, R‐(+)‐WIN 55,212‐2 and S‐(−)‐WIN 55,212‐3 relax rat small mesenteric artery mainly by inhibiting Ca2+ influx into vascular smooth muscle. Anandamide causes vasorelaxation by activating vanilloid receptors, but may also inhibit Ca2+ entry. Relaxation to JWH 015 and anandamide was sensitive to SR 141716A, but there is no other evidence for the involvement of CB1 or CB2 receptors in responses to these compounds.
British Journal of Pharmacology (2003) 139, 585–597. doi:10.1038/sj.bjp.0705280
Anandamide activates CB(1) cannabinoid receptors but also has effects, particularly in the vasculature, that cannot be explained by actions at either this or the other cloned cannabinoid receptor, ...the CB(2) receptor. These effects are probably mediated by a novel G protein-coupled receptor, but genome searching has not revealed a strong candidate. Several approaches have suggested that an orphan receptor, GPR55, is a target for anandamide, but the pharmacology of this receptor is such that it cannot be categorically identified as a cannabinoid receptor. GPR55 appears primarily to be a receptor for lysophosphatidylinositol which may exhibit biased agonism, leading to it also responding to anandamide. GPR55 activates G(alpha12) and G(alpha13) and thence RhoA, leading to an oscillatory intracellular Ca(2+) signal. Further complexity arises from possible interactions between the anandamide-sensitive CB(1) receptor and GPR55. Overall, it appears that GPR55 has several signaling modalities and that, while anandamide can activate systems containing this receptor, GPR55 cannot yet be primarily designated a receptor for this endocannabinoid.
Cannabinoids include not only plant-derived compounds (of which Δ9-tetrahydrocannabinol is the primary psychoactive ingredient of cannabis), but also synthetic agents and endogenous substances termed ...endocannabinoids which include anandamide (2-arachidonoylethanolamide) and 2-arachidonoylglycerol. Cannabinoids act on specific, G-protein-coupled, receptors which are currently divided into two types, CB1 and CB2. Relatively selective agonists and antagonists for these receptors have been developed, although one agent (SR141716A) widely used as an antagonist at CB1 receptors has non-cannabinoid receptor-mediated effects at concentrations which are often used to define the presence of the CB1 receptor. Both cannabinoid receptors are primarily coupled to Gi/o proteins and act to inhibit adenylyl cyclase. Stimulation of CB1 receptors also modulates the activity of K+ and Ca2+ channels and of protein kinase pathways including protein kinase B (Akt) which might mediate effects on apoptosis. CB1 receptors may activate the extracellular signal-regulated kinase cascade through ceramide signalling. Cannabinoid actions on the cardiovascular system have been widely interpreted as being mediated by CB1 receptors although there are a growing number of observations, particularly in isolated heart and blood vessel preparations, that suggest that other cannabinoid receptors may exist. Interestingly, the currently identified cannabinoid receptors appear to be related to a wider family of lipid receptor, those for the lysophospholipids, which are also linked to Gi/o protein signalling. Anandamide also activates vanilloid VR1 receptors on sensory nerves and releases the vasoactive peptide, calcitonin gene-related peptide (CGRP), which brings about vasodilatation through its action on CGRP receptors. Current evidence suggests that endocannabinoids have important protective roles in pathophysiological conditions such as shock and myocardial infarction. Therefore, their cardiovascular effects and the receptors mediating them are the subject of increasing investigative interest.
Tracking the Evolution of Non–Small-Cell Lung Cancer Jamal-Hanjani, Mariam; Wilson, Gareth A; McGranahan, Nicholas ...
New England journal of medicine/The New England journal of medicine,
06/2017, Letnik:
376, Številka:
22
Journal Article
Recenzirano
Odprti dostop
Distinct genes are mutated in different regions of a single patient’s tumor. Point mutations seem to have less adverse effect on relapse-free survival than copy-number heterogeneity. Chromosome ...instability appears to be an important adverse prognostic factor.
Lung cancer is the leading cause of cancer-related death worldwide,
1
,
2
with non–small-cell lung cancer (NSCLC) being the most common type. Large-scale sequencing studies have revealed the complex genomic landscape of NSCLC
3
–
6
and genomic differences between lung adenocarcinomas and lung squamous-cell carcinomas.
7
However, in-depth exploration of NSCLC intratumor heterogeneity (which provides the fuel for tumor evolution and drug resistance) and cancer genome evolution has been limited to small retrospective cohorts.
8
,
9
Therefore, the clinical significance of intratumor heterogeneity and the potential for clonality of driver events to guide therapeutic strategies have not yet been defined.
Tracking Non–Small-Cell Lung Cancer . . .
In order to test the hypothesis that angiotensin II exacerbates myocardial ischaemia‐reperfusion (IR) injury, we examined the effects of graded angiotension II concentrations of angiotensin II on IR ...injury in both working and non‐working (Langendorff) isolated rat hearts.
Non‐working hearts were subjected to 30 min aerobic perfusion (baseline) then 25 min of global, no‐flow ischaemia followed by 30 min of reperfusion either in the absence (control, n=7) or presence of 1 (n=6) or 10 nM (n=5) angiotensin II). Recoveries of LV developed pressure and coronary flow after 30 min reperfusion in control hearts (58±9 and 40±8% of baseline levels, respectively) were no different from hearts treated with 1 or 10 nM angiotensin II. Infarct size (determined at the end of reperfusion by triphenyltetrazolium chloride staining) was reduced by angiotensin II in a concentration‐dependent manner (from a control value of 27±3 to 18±4% and 9±3% of the LV, respectively).
Working hearts were subjected to 50 min pre‐ischaemic (pre‐I) aerobic perfusion then 30 min of global, no‐flow ischaemia followed by 30 min of reperfusion either in the absence (control, n=14) or presence of 1 (n=8), 10 (n=7) or 100 nM (n=7) angiotensin II). In controls, post‐ischaemic (post‐I) left ventricular (LV) work and efficiency of oxygen consumption were depressed (43±9 and 42±10% of pre‐I levels, respectively). The presence of angiotensin II throughout IR had no effect on LV work compared with control.
Thus, angiotensin II reduces infarct size in a concentration‐dependent manner but has no effect on contractile stunning associated with IR in isolated rat hearts.
British Journal of Pharmacology (2001) 134, 38–45; doi:10.1038/sj.bjp.0704225
Membrane potential responses of rat mesenteric endothelial cells were investigated in intact arteries using sharp electrodes. Levcromakalim, an activator of ATP-sensitive K
+ channels (K
ATP) induced ...concentration-dependent hyperpolarisation of the endothelial cells, which was reversible by glibenclamide and ciclazindol, inhibitors of K
ATP. Another K
ATP activator, diazoxide, also hyperpolarised the endothelial cells. Carbachol induced endothelial hyperpolarisation that was inhibited by combinations of apamin and charybdotoxin, but not Ba
2+ and ouabain. Prior stimulation with levcromakalim inhibited carbachol-induced responses, and this inhibitory effect was also sensitive to glibenclamide. 1,3-dihydro-1-2-hydroxy-5-(trifluoromethyl)phenyl-5-(trifluoromethyl)-2
H-benzimidazol-2-one (NS 1619), an activator of large conductance, Ca
2+-activated K
+ channels (BK
Ca), induced only small hyperpolarisations of the endothelial cells. Preincubation of tissues with 18α- or 18β-glycyrrhetinic acid, inhibitors of gap junction communication, increased the input resistance and depolarised the endothelial cells, and inhibited the hyperpolarising effect of levcromakalim. It is concluded that activation of K
ATP causes hyperpolarisation of rat mesenteric endothelial cells, probably through gap junctional transfer of smooth muscle hyperpolarisation, and that this may represent an important modulator of endothelial function.
Endocannabinoid production by platelets and macrophages is increased in circulatory shock. This may be protective of the cardiovascular system as blockade of CB1 cannabinoid receptors exacerbates ...endothelial dysfunction in haemorrhagic and endotoxin shock and reduces survival. Now evidence suggests that blockade of CB1 receptors starting 24 h after myocardial infarction in rats has a deleterious effect on cardiac performance, while use of a nonselective cannabinoid receptor agonist prevents hypotension and reduces endothelial dysfunction, although left ventricular end diastolic pressure is elevated. Cannabinoids and endocannabinoid systems may therefore present useful targets for therapy following myocardial infarction.
British Journal of Pharmacology (2003) 138, 1183–1184. doi:10.1038/sj.bjp.0705155
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