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The endogenous cannabinoid receptor agonist anandamide is a powerful vasodilator of isolated vascular preparations, but its mechanism of action is unclear. Here we show that the vasodilator response to anandamide in isolated arteries is capsaicin-sensitive and accompanied by release of calcitonin- gene-related peptide (CGRP). The selective CGRP-receptor antagonist 8-37 CGRP (ref. 5), but not the c

1. In rat isolated hepatic arteries contracted with phenylephrine, acetylcholine and the calcium ionophore A23187 each elicit endothelium-dependent relaxations, which involve both nitric oxide (NO) and endothelium-derived hyperpolarizing factor (EDHF). However, the contribution of prostanoids to these responses, and the potential interaction between EDHF and other endothelium-derived relaxing fact

A blog-post on a performance of The Taming of the Shrew by LU students.

In the guinea pig basilar artery, acetylcholine and the calcium ionophore A23187 induced endothelium-dependent relaxations, which were not significantly affected by the nitric oxide (NO) synthase inhibitor N(ω)- nitro-L-arginine (L-NOARG; 0.3 mM) or the guanylate cyclase inhibitor ODQ (1H-[1,2,4]oxadiazolo[4,3-a]quinoxaline-1-one; 1-10 μM), or by these inhibitors combined. However, acetylcholine (

1. The effects of anandamide on K+ currents and membrane potential have been examined in freshly-isolated smooth muscle cells from rat hepatic artery and the results compared with the effects of this arachidonic acid derivative on tension and membrane potential changes in segments of whole artery. 2. In the presence of 0.3 mM L-NOARG and 10 μM indomethacin, anandamide (0.1-100 μM) and endothelium-

1. In the rat hepatic artery, the acetylcholine-induced relaxation mediated by endothelium-derived hyperpolarizing factor (EDHF) is abolished by a combination of apamin and charybdotoxin, inhibitors of small (SK(Ca)) and large (BK(Ca)) conductance calcium-sensitive potassium (K)-channels, respectively, but not by each toxin alone. The selective BK(Ca) inhibitor iberiotoxin cannot replace charybdot

1. In the presence of N(G)-nitro-L-arginine (L-NOARG, 0.3 mM) and indomethacin (10 μM), the relaxations induced by acetylcholine and the calcium (Ca) ionophore A23187 are considered to be mediated by endothelium-derived hyperpolarizing factor (EDHF) in the guinea-pig basilar artery. 2. Inhibitors of adenosine 5'-triphosphate (ATP)-sensitive potassium (K)-channels (K(ATP); glibenclamide, 10 μM), vo

1. The possibility that the endothelium-derived hyperpolarising factor (EDHF) in the rat hepatic artery is a cytochrome P450 mono-oxygenase metabolite of arachidonic acid was examined in the present study. In this preparation, acetylcholine elicits EDHF-mediated relaxations in the presence of the nitric oxide (NO) synthase and cyclo-oxygenase inhibitors N(ω)-nitro-L-arginine (L-NOARG) and indometh

1. In the presence of indomethacin (IM, 10 μM) and N(ω)-nitro-L-arginine (L-NOARG, 0.3 mM), acetylcholine (ACh) induces an endothelium-dependent smooth muscle hyperpolarization and relaxation in the rat isolated hepatic artery. The potassium (K) channel inhibitors, tetrabutylammonium (TBA, 1 mM) and to a lesser extent 4-aminopyridine (4-AP, 1 mM) inhibited the L-NOARG/IM-resistant relaxation induc

1. The effects of the cytochrome P450 inhibitors, proadifen, clotrimazole and 17-octadecynoic acid (17-ODYA) on K-currents in freshly-isolated single cells derived from rat portal vein and on mechanical activity in whole veins were studied. 2. When cells were stepped from -90 mV to a series of test potentials (from -80 to +50 mV), a delayed rectifier current (I(K(V))) and an A-type current ((IK(A)

Electrical field stimulation (EFS) of the rabbit urethral lamina propria elicited a frequency‐dependent non‐adrenergic, non‐cholinergic (NANC) relaxation, which was abolished by NΩ–nitro‐L‐arginine (l‐NOARG). Ω‐Conotoxin GVIA, a selective blocker of N‐type voltage‐operated calcium channels (VOCCs), and Ω‐conotoxin MVIIC (blocker of N‐ and Q‐type VOCCs) inhibited the NANC relaxation, and the inhibi

Relaxant effects of acetylcholine (ACh), histamine, calcitonin gene‐related peptide (CGRP) and the calcium ionophore A23187 were examined in rat femoral (Ø ≅ 0.2 mm), mesenteric (0.2 mm), intrarenal (0.2 mm) and hepatic (0.3 mm) arteries, and aorta (2 mm). Acetylcholine elicited an endothelium‐dependent relaxation in all arteries. Histamine induced an endothelium‐dependent relaxation in aorta, and

Nitric oxide (NO)‐independent pathways contributing to acetylcholine (ACh)‐induced relaxation were examined in the rat isolated hepatic artery and aorta at low and high levels of precontraction induced by phenylephrine (PhE). In the hepatic artery, the ACh‐induced relaxation was unaffected by the NO synthase inhibitors Nw‐nitro‐L‐arginine (L‐NOARG, 0.3 mM) and Nω‐nitro‐L‐arginine methyl ester (0.1

Acetylcholine (ACh) induces an Nω–nitro–L–arginine (L–NOARG)–resistant relaxation and hyperpolarization in the rat isolated hepatic artery. The possibility that carbon monoxide (CO) produced by haem oxygenase (HO) is an endogenous mediator of this response was investigated. Exogenously applied CO evoked a concentration–dependent relaxation, and the CO ‘scavenger’ oxyhaemoglobin (10μM) reduced the

The rat hepatic artery responds to acetylcholine (ACh) with an endothelium‐dependent relaxation, which is unaffected by nitric oxide (NO) synthase and cyclooxygenase inhibition. The purpose of this study was to investigate whether the NO‐independent relaxation is caused by hyperpolarization of the smooth muscle cells. In vessels with endothelium ACh induced a hyperpolarization in the presence of 0

The effects of ω‐conotoxin GVIA (an inhibitor of N‐type voltage‐operated calcium channels; VOCCs) were compared on adrenergic, cholinergic and non‐adrenergic, non‐cholinergic (NANC) responses induced by electrical field stimulation (EFS) in the rabbit urethra and detrusor. EFS induced a relaxation in urethral smooth muscle and lamina propria precontracted by arginine vasopressin (AVP). The relaxat

The calcium antagonistic properties of (+)‐T‐cadinol, some of its stereoisomers and related terpenes were investigated in both functional and radioligand binding studies, and the effects were compared with those of the dihydropyridine calcium antagonist (±)‐nimodipine. In the isolated rat aorta, the terpenes relaxed contractions induced by 60 mM K+ more potently than those induced by phenylephrine

Abstract: (+)‐T‐Cadinol is a sesquiterpene with smooth muscle relaxing properties. In the isolated rat aorta, T‐cadinol relaxed contractions induced by 60 mM K+ in a concentration‐dependent fashion. The dihydropyridine calcium antagonist nimodipine was approximately 4,000 times more potent than T‐cadinol. While both drugs nearly abolished the K+‐induced contractions, they only partially relaxed co

The smooth muscle relaxing effect of the sesquiterpene T‐cadinol, isolated from scented myrrh (resin of Commiphora guidottii Chiov., Burseraceae), was investigated. The compound inhibited the contractile responses in the isolated guinea‐pig ileum to histamine, carbachol, Ba2+ and K+ in a concentration dependent and reversible manner. The antagonism of the receptor‐mediated contractions induced by

1. 1. The effects of progresterone, corticosterone 21-acetate, chlormadinone acetate, dehydroepi-androsterone 3-sulfate and lysophosphatidylcholine were tested on 86Rb-uptake, 3H-5-HT-uptake, ADP-induced aggregation and 5-HT-induced shape change in human platelets. Ouabain and digoxin were used for reference. 2. 2. Ouabain and digoxin 10-5 M inhibited 86Rb-uptake by more than 85%, and chlormadinon