Biomaterial Database

8-Bromo cyclic guanosine monophosphate mimics the actions of nitroglycerin on alpha-adrenergic mechanisms in canine saphenous vein. 1987

H Eskinder, and G J Gross

The purpose of the present study was to determine if 8-bromo cyclic guanosine monophosphate (cGMP) mimics the actions of nitroglycerin in inhibiting alpha 1- versus alpha 2-mediated constrictor responses in vitro using rings prepared from isolated canine saphenous vein. Contractions were produced by phenylephrine, a selective alpha 1-adrenoceptor agonist and B-HT 920, a selective alpha 2-adrenoceptor agonist. The inhibitory effects of nitroglycerin and 8-bromo cGMP on contractions produced by submaximal concentrations (EC75) of phenylephrine and B-HT 920 were determined. 8-Bromo cGMP like nitroglycerin produced a selective antagonism of alpha 2-adrenoceptor-mediated responses and had minimal effects on alpha 1-adrenoceptor-induced constriction. However, after removal of spare postsynaptic vascular alpha 1-adrenoceptors by treatment with the irreversible alpha-adrenoceptor antagonist phenoxybenzamine (5 X 10(-8) M, 1 X 10(-7) M), the alpha 1-adrenoceptor-mediated vasoconstrictor responses of phenylephrine became highly sensitive to antagonism by 8-bromo cGMP and nitroglycerin. These data suggest that the action of 8-bromo cGMP like nitroglycerin is 'buffered' by the presence of a large alpha 1-adrenoceptor reserve in canine saphenous vein. The similarity in the efficacy and potency of these two agents suggests that the effects of nitroglycerin in canine saphenous vein may be the result of an increase in intracellular cGMP.

UI	MeSH Term	Description	Entries
D008297	Male		Males
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
D010656	Phenylephrine	An alpha-1 adrenergic agonist used as a mydriatic, nasal decongestant, and cardiotonic agent.	(R)-3-Hydroxy-alpha-((methylamino)methyl)benzenemethanol,Metaoxedrin,Metasympatol,Mezaton,Neo-Synephrine,Neosynephrine,Phenylephrine Hydrochloride,Phenylephrine Tannate,Neo Synephrine,Tannate, Phenylephrine
D011942	Receptors, Adrenergic, alpha	One of the two major pharmacological subdivisions of adrenergic receptors that were originally defined by the relative potencies of various adrenergic compounds. The alpha receptors were initially described as excitatory receptors that post-junctionally stimulate SMOOTH MUSCLE contraction. However, further analysis has revealed a more complex picture involving several alpha receptor subtypes and their involvement in feedback regulation.	Adrenergic alpha-Receptor,Adrenergic alpha-Receptors,Receptors, alpha-Adrenergic,alpha-Adrenergic Receptor,alpha-Adrenergic Receptors,Receptor, Adrenergic, alpha,Adrenergic alpha Receptor,Adrenergic alpha Receptors,Receptor, alpha-Adrenergic,Receptors, alpha Adrenergic,alpha Adrenergic Receptor,alpha Adrenergic Receptors,alpha-Receptor, Adrenergic,alpha-Receptors, Adrenergic
D002118	Calcium	A basic element found in nearly all tissues. It is a member of the alkaline earth family of metals with the atomic symbol Ca, atomic number 20, and atomic weight 40. Calcium is the most abundant mineral in the body and combines with phosphorus to form calcium phosphate in the bones and teeth. It is essential for the normal functioning of nerves and muscles and plays a role in blood coagulation (as factor IV) and in many enzymatic processes.	Coagulation Factor IV,Factor IV,Blood Coagulation Factor IV,Calcium-40,Calcium 40,Factor IV, Coagulation
D004285	Dogs	The domestic dog, Canis familiaris, comprising about 400 breeds, of the carnivore family CANIDAE. They are worldwide in distribution and live in association with people. (Walker's Mammals of the World, 5th ed, p1065)	Canis familiaris,Dog
D004305	Dose-Response Relationship, Drug	The relationship between the dose of an administered drug and the response of the organism to the drug.	Dose Response Relationship, Drug,Dose-Response Relationships, Drug,Drug Dose-Response Relationship,Drug Dose-Response Relationships,Relationship, Drug Dose-Response,Relationships, Drug Dose-Response
D005260	Female		Females
D005996	Nitroglycerin	A volatile vasodilator which relieves ANGINA PECTORIS by stimulating GUANYLATE CYCLASE and lowering cytosolic calcium. It is also sometimes used for TOCOLYSIS and explosives.	Glyceryl Trinitrate,Anginine,Dynamite,Gilustenon,Nitrangin,Nitro-Bid,Nitro-Dur,Nitrocard,Nitroderm,Nitroderm TTS,Nitroglyn,Nitrol,Nitrolan,Nitrong,Nitrospan,Nitrostat,Perlinganit,Susadrin,Sustac,Sustak,Sustonit,Transderm Nitro,Tridil,Trinitrin,Trinitrolong,Nitro Bid,Nitro Dur,NitroBid,NitroDur,Trinitrate, Glyceryl
D006152	Cyclic GMP	Guanosine cyclic 3',5'-(hydrogen phosphate). A guanine nucleotide containing one phosphate group which is esterified to the sugar moiety in both the 3'- and 5'-positions. It is a cellular regulatory agent and has been described as a second messenger. Its levels increase in response to a variety of hormones, including acetylcholine, insulin, and oxytocin and it has been found to activate specific protein kinases. (From Merck Index, 11th ed)	Guanosine Cyclic 3',5'-Monophosphate,Guanosine Cyclic 3,5 Monophosphate,Guanosine Cyclic Monophosphate,Guanosine Cyclic-3',5'-Monophosphate,3',5'-Monophosphate, Guanosine Cyclic,Cyclic 3',5'-Monophosphate, Guanosine,Cyclic Monophosphate, Guanosine,Cyclic-3',5'-Monophosphate, Guanosine,GMP, Cyclic,Guanosine Cyclic 3',5' Monophosphate,Monophosphate, Guanosine Cyclic