Biomaterial Database

Comparison of agonistic and antagonistic actions of guanabenz and guanfacin on alpha 1 and alpha 2-adrenoceptors in isolated smooth muscles. 1987

K Takeuchi, and M Kogure, and T Hashimoto

The effects of guanabenz, guanfacine and clonidine on alpha-adrenoceptors were investigated in isolated rat vas deferens and rabbit aortic strip. All 3 drugs at low concentrations (10(-9)-10(-8) M) caused inhibition of twitch responses of the rat vas deferens induced by nerve stimulation. These effects were competitively antagonized by yohimbine. Guanfacine and clonidine at relatively high concentrations (10(-6)-10(-4) M) produced contractions of the rat vas deferens which were antagonized by prazosin. These contractile responses were not much affected by denervation. Prazosin-sensitive contractions by guanfacine and clonidine were also observed in the rabbit aortic strip, which were not affected by reserpine pretreatment. In both tissues, the intrinsic activity of guanfacine was almost identical to that of norepinephrine, whereas that of clonidine was less than one half. Guanabenz and clonidine showed a competitive antagonistic effect against norepinephrine and phenylephrine in both the rat vas deferens and rabbit aorta, the antagonisms being similar in potency. The results indicate that all 3 drugs are potent agonists on the presynaptic alpha 2-adrenoceptor. In contrast, on the postsynaptic alpha 1-adrenoceptor, guanfacine and guanabenz showed only agonistic and antagonistic actions, respectively, whereas clonidine exhibited partial agonistic characteristics.

UI	MeSH Term	Description	Entries
D008297	Male		Males
D009121	Muscle Denervation	The resection or removal of the innervation of a muscle or muscle tissue.	Denervation, Muscle,Denervations, Muscle,Muscle Denervations
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
D009131	Muscle, Smooth, Vascular	The nonstriated involuntary muscle tissue of blood vessels.	Vascular Smooth Muscle,Muscle, Vascular Smooth,Muscles, Vascular Smooth,Smooth Muscle, Vascular,Smooth Muscles, Vascular,Vascular Smooth Muscles
D010648	Phenylacetates	Derivatives of phenylacetic acid. Included under this heading are a variety of acid forms, salts, esters, and amides that contain the benzeneacetic acid structure. Note that this class of compounds should not be confused with derivatives of phenyl acetate, which contain the PHENOL ester of ACETIC ACID.	Benzeneacetates,Benzeneacetic Acids,Phenylacetic Acids,Acids, Benzeneacetic,Acids, Phenylacetic
D011919	Rats, Inbred Strains	Genetically identical individuals developed from brother and sister matings which have been carried out for twenty or more generations or by parent x offspring matings carried out with certain restrictions. This also includes animals with a long history of closed colony breeding.	August Rats,Inbred Rat Strains,Inbred Strain of Rat,Inbred Strain of Rats,Inbred Strains of Rats,Rat, Inbred Strain,August Rat,Inbred Rat Strain,Inbred Strain Rat,Inbred Strain Rats,Inbred Strains Rat,Inbred Strains Rats,Rat Inbred Strain,Rat Inbred Strains,Rat Strain, Inbred,Rat Strains, Inbred,Rat, August,Rat, Inbred Strains,Rats Inbred Strain,Rats Inbred Strains,Rats, August,Rats, Inbred Strain,Strain Rat, Inbred,Strain Rats, Inbred,Strain, Inbred Rat,Strains, Inbred Rat
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
D003000	Clonidine	An imidazoline sympatholytic agent that stimulates ALPHA-2 ADRENERGIC RECEPTORS and central IMIDAZOLINE RECEPTORS. It is commonly used in the management of HYPERTENSION.	Catapres,Catapresan,Catapressan,Chlophazolin,Clofelin,Clofenil,Clonidine Dihydrochloride,Clonidine Hydrochloride,Clonidine Monohydrobromide,Clonidine Monohydrochloride,Clopheline,Dixarit,Gemiton,Hemiton,Isoglaucon,Klofelin,Klofenil,M-5041T,ST-155,Dihydrochloride, Clonidine,Hydrochloride, Clonidine,M 5041T,M5041T,Monohydrobromide, Clonidine,Monohydrochloride, Clonidine,ST 155,ST155
D006143	Guanabenz	An alpha-2 selective adrenergic agonist used as an antihypertensive agent.	2,6-Dichlorobenzylideneaminoguanidine,BR-750,Guanabenz Acetate,Guanabenz Monoacetate,WY-8678,Wyeth-Ayerst of Guanabenz Acetate,Wytensin,2,6 Dichlorobenzylideneaminoguanidine,Acetate Wyeth-Ayerst, Guanabenz,Acetate, Guanabenz,BR 750,BR750,Guanabenz Acetate Wyeth-Ayerst,Monoacetate, Guanabenz,WY 8678,WY8678,Wyeth Ayerst of Guanabenz Acetate
D006146	Guanidines	A family of iminourea derivatives. The parent compound has been isolated from mushrooms, corn germ, rice hulls, mussels, earthworms, and turnip juice. Derivatives may have antiviral and antifungal properties.