Biomaterial Database

Effects of St-587 on the alpha-adrenoceptors in the bisected rat vas deferens. 1989

A Badia, and J Sallés

Departament de Farmacologia i Psiquiatria, Universitat Autònoma de Barcelona, Spain.

The effects of the alpha-adrenoceptor agonist St-587 have been studied on the twitch responses induced by field stimulation in the prostatic portion of rat vas deferens. Moreover the drug's influence on the unstimulated prostatic and epididymal halves of rat vas deferens has also been determined. Alone and after addition of yohimbine (0.3 microM) it enhanced in a concentration-dependent manner the twitch responses in the prostatic half. Prazosin competitively antagonized (pA2 = 8.41 +/- 0.03) this effect. The enhancing effect of St-587 was not reduced in reserpinized animals. These results suggest that post-synaptic alpha 1-adrenoceptors are involved in the potentiation of twitch responses induced by St-587. When alpha 1-adrenoceptors were blocked by prazosin (0.1 microM), St-587 partially inhibited the twitch responses of the prostatic portion of rat vas deferens (Emax = 49.5 +/- 3.5%). Yohimbine completely reversed the inhibitory effects of both St-587 and clonidine. Furthermore St-587 antagonized the inhibitory effects of clonidine on twitch responses. Thus it appears that St-587 also behaves as a partial agonist of presynaptic alpha 2-adrenoceptors in this portion of rat vas deferens, but it did not induce contractions in the unstimulated prostatic half of the vas deferens. However, it competitively antagonized the alpha 1-adrenoceptor agonist phenylephrine by acting as an antagonist of prostatic postsynaptic alpha 1 adrenoceptors. These alpha 1-adrenoceptors are probably different from those that mediate the twitch enhancing response to St-587 in that portion. On the other hand, St-587 was a partial agonist of alpha 1-adrenoceptors in the epididymal half.(ABSTRACT TRUNCATED AT 250 WORDS)

UI	MeSH Term	Description	Entries
D008297	Male		Males
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
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
D011224	Prazosin	A selective adrenergic alpha-1 antagonist used in the treatment of HEART FAILURE; HYPERTENSION; PHEOCHROMOCYTOMA; RAYNAUD DISEASE; PROSTATIC HYPERTROPHY; and URINARY RETENTION.	Furazosin,Minipress,Pratsiol,Prazosin HCL,Prazosin Hydrochloride,HCL, Prazosin,Hydrochloride, Prazosin
D011467	Prostate	A gland in males that surrounds the neck of the URINARY BLADDER and the URETHRA. It secretes a substance that liquefies coagulated semen. It is situated in the pelvic cavity behind the lower part of the PUBIC SYMPHYSIS, above the deep layer of the triangular ligament, and rests upon the RECTUM.	Prostates
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
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
D004822	Epididymis	The convoluted cordlike structure attached to the posterior of the TESTIS. Epididymis consists of the head (caput), the body (corpus), and the tail (cauda). A network of ducts leaving the testis joins into a common epididymal tubule proper which provides the transport, storage, and maturation of SPERMATOZOA.