Biomaterial Database

Differential inhibition of alpha-1 vs. alpha-2 adrenoceptor-mediated responses in canine saphenous vein by nitroglycerin. 1986

H Eskinder, and G J Gross

In the present investigation, the subtype of alpha adrenoceptor that is preferentially antagonized by the noncalcium entry blocker, nitroglycerin (GTN), was studied in vitro using rings prepared from isolated canine saphenous vein (CSV). The calcium entry blocker, diltiazem (DZ), was used for purposes of comparison. Contractions were produced by the following alpha adrenergic agonists: norepinephrine (NE), a nonselective alpha adrenoceptor agonist, phenylephrine (PE), a selective alpha-1 adrenoceptor agonist and B-HT 920, a selective alpha-2 adrenoceptor agonist. The inhibitory effects of GTN on contractions produced by submaximal concentrations (EC65 to EC75) of NE, PE and B-HT 920 were determined. GTN was found to inhibit preferentially the postsynaptic alpha-2 adrenoceptor-mediated responses to B-HT 920 while producing minimal effects on those produced by NE or PE. Similar results were found with DZ. However, when a portion of the alpha-1 adrenoceptor pool was inactivated by phenoxybenzamine (5 X 10(-8) to 1 X 10(-7) M), GTN and DZ both produced a significant depression of responses to PE, a full alpha-1 adrenoceptor agonist. In addition, contractions produced by l-dobutamine, a selective partial alpha-1 adrenoceptor agonist (no alpha receptor reserve), were highly sensitive to inhibition by GTN. These results suggest that the selective inhibition of contractions mediated by postjunctional alpha-2 vs. alpha-1 adrenoceptors in CSV by GTN and DZ may be due partially to the presence of a large alpha-1 adrenoceptor reserve that conceals an underlying functional antagonism to alpha-1 adrenoceptor-mediated responses.(ABSTRACT TRUNCATED AT 250 WORDS)

UI	MeSH Term	Description	Entries
D008297	Male		Males
D010643	Phenoxybenzamine	An alpha-adrenergic antagonist with long duration of action. It has been used to treat hypertension and as a peripheral vasodilator.	Dibenylene,Dibenyline,Dibenziran,Dibenzylin,Dibenzyline,Dibenzyran,Phenoxybenzamine Hydrochloride,Hydrochloride, Phenoxybenzamine
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
D004110	Diltiazem	A benzothiazepine derivative with vasodilating action due to its antagonism of the actions of CALCIUM ion on membrane functions.	Aldizem,CRD-401,Cardil,Cardizem,Dilacor,Dilacor XR,Dilren,Diltiazem Hydrochloride,Diltiazem Malate,Dilzem,Tiazac,CRD 401,CRD401
D004280	Dobutamine	A catecholamine derivative with specificity for BETA-1 ADRENERGIC RECEPTORS. It is commonly used as a cardiotonic agent after CARDIAC SURGERY and during DOBUTAMINE STRESS ECHOCARDIOGRAPHY.	Dobucor,Dobuject,Dobutamin Fresenius,Dobutamin Hexal,Dobutamin Solvay,Dobutamin-ratiopharm,Dobutamina Inibsa,Dobutamina Rovi,Dobutamine (+)-Isomer,Dobutamine Hydrobromide,Dobutamine Hydrochloride,Dobutamine Lactobionate,Dobutamine Phosphate (1:1) Salt, (-)-Isomer,Dobutamine Tartrate,Dobutamine Tartrate (1:1), (R-(R,R))-Isomer,Dobutamine Tartrate (1:1), (S-(R,R))-Isomer,Dobutamine, (-)-Isomer,Dobutamine, Phosphate (1:1) Salt (+)-Isomer,Dobutrex,Lilly 81929,Oxiken,Posiject,Dobutamin ratiopharm,Hydrobromide, Dobutamine,Hydrochloride, Dobutamine,Lactobionate, Dobutamine,Tartrate, Dobutamine
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
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
D000818	Animals	Unicellular or multicellular, heterotrophic organisms, that have sensation and the power of voluntary movement. Under the older five kingdom paradigm, Animalia was one of the kingdoms. Under the modern three domain model, Animalia represents one of the many groups in the domain EUKARYOTA.	Animal,Metazoa,Animalia