Biomaterial Database

Inhibition by ethacrynic acid of NO-mediated relaxations of the rat anococcygeus muscle. 1994

C G Li, and S F Brosch, and M J Rand

Department of Pharmacology, University of Melbourne, Parkville, Victoria, Australia.

1. The effects of ethacrynic acid were studied on relaxations elicited by nitric oxide (NO), the NO-donors sodium nitroprusside (SNP) and glyceryl trinitrate (GTN), nitrergic nerve stimulation and the NO-independent agent papaverine in isolated preparations of rat anococcygeus muscles. 2. Ethacrynic acid (100 mumol/L) produced complete relaxation of partially contracted anococcygeus muscles, but the tone recovered after the ethacrynic acid was washed out. Following exposure to ethacrynic acid, the relaxant responses to NO, SNP, GTN and nitrergic nerve stimulation were abolished or markedly reduced; however, the response to papaverine was only slightly reduced. 3. The presence of 3 mmol/L L-cysteine during the period of exposure to ethacrynic acid prevented the inhibition of the relaxing effects of SNP, GTN and nitrergic nerve stimulation almost completely, but did not affect the slight reduction in responses to papaverine. 4. The addition of L-cysteine (3 mmol/L) after incubation with ethacrynic acid did not significantly affect the inhibited responses to SNP and GTN; however, the inhibited responses to nitrergic nerve stimulation were slightly but significantly increased. 5. The results suggest that endogenous sulphydryl groups are required for the actions of NO, NO-donating drugs and the nitrergic transmitter in the rat anococcygeus muscle and possibly for the synthesis or release of the nitrergic transmitter.

UI	MeSH Term	Description	Entries
D008297	Male		Males
D009126	Muscle Relaxation	That phase of a muscle twitch during which a muscle returns to a resting position.	Muscle Relaxations,Relaxation, Muscle,Relaxations, Muscle
D009130	Muscle, Smooth	Unstriated and unstriped muscle, one of the muscles of the internal organs, blood vessels, hair follicles, etc. Contractile elements are elongated, usually spindle-shaped cells with centrally located nuclei. Smooth muscle fibers are bound together into sheets or bundles by reticular fibers and frequently elastic nets are also abundant. (From Stedman, 25th ed)	Muscle, Involuntary,Smooth Muscle,Involuntary Muscle,Involuntary Muscles,Muscles, Involuntary,Muscles, Smooth,Smooth Muscles
D009569	Nitric Oxide	A free radical gas produced endogenously by a variety of mammalian cells, synthesized from ARGININE by NITRIC OXIDE SYNTHASE. Nitric oxide is one of the ENDOTHELIUM-DEPENDENT RELAXING FACTORS released by the vascular endothelium and mediates VASODILATION. It also inhibits platelet aggregation, induces disaggregation of aggregated platelets, and inhibits platelet adhesion to the vascular endothelium. Nitric oxide activates cytosolic GUANYLATE CYCLASE and thus elevates intracellular levels of CYCLIC GMP.	Endogenous Nitrate Vasodilator,Mononitrogen Monoxide,Nitric Oxide, Endothelium-Derived,Nitrogen Monoxide,Endothelium-Derived Nitric Oxide,Monoxide, Mononitrogen,Monoxide, Nitrogen,Nitrate Vasodilator, Endogenous,Nitric Oxide, Endothelium Derived,Oxide, Nitric,Vasodilator, Endogenous Nitrate
D009599	Nitroprusside	A powerful vasodilator used in emergencies to lower blood pressure or to improve cardiac function. It is also an indicator for free sulfhydryl groups in proteins.	Nitroferricyanide,Sodium Nitroprusside,Cyanonitrosylferrate,Ketostix,Naniprus,Nipride,Nipruton,Nitriate,Nitropress,Nitroprussiat Fides,Nitroprusside, Disodium Salt,Nitroprusside, Disodium Salt, Dihydrate,Disodium Salt Nitroprusside,Nitroprusside, Sodium
D010208	Papaverine	An alkaloid found in opium but not closely related to the other opium alkaloids in its structure or pharmacological actions. It is a direct-acting smooth muscle relaxant used in the treatment of impotence and as a vasodilator, especially for cerebral vasodilation. The mechanism of its pharmacological actions is not clear, but it apparently can inhibit phosphodiesterases and it may have direct actions on calcium channels.	Cerespan,Papaverine Hydrochloride,Pavabid,Pavatym,Hydrochloride, Papaverine
D003545	Cysteine	A thiol-containing non-essential amino acid that is oxidized to form CYSTINE.	Cysteine Hydrochloride,Half-Cystine,L-Cysteine,Zinc Cysteinate,Half Cystine,L Cysteine
D004347	Drug Interactions	The action of a drug that may affect the activity, metabolism, or toxicity of another drug.	Drug Interaction,Interaction, Drug,Interactions, Drug
D004558	Electric Stimulation	Use of electric potential or currents to elicit biological responses.	Stimulation, Electric,Electrical Stimulation,Electric Stimulations,Electrical Stimulations,Stimulation, Electrical,Stimulations, Electric,Stimulations, Electrical
D004976	Ethacrynic Acid	A compound that inhibits symport of sodium, potassium, and chloride primarily in the ascending limb of Henle, but also in the proximal and distal tubules. This pharmacological action results in excretion of these ions, increased urinary output, and reduction in extracellular fluid. This compound has been classified as a loop or high ceiling diuretic.	Edecrin,Etacrynic Acid,Ethacrinic Acid,Ethacrynate Sodium,Ethacrynic Acid, Sodium Salt,Hydromedin,Acid, Etacrynic,Acid, Ethacrinic,Acid, Ethacrynic,Sodium, Ethacrynate