Biomaterial Database

Agonist action of yohimbine on the perfused rabbit central ear artery. 1982

F M Tayo

The agonist action of yohimbine, an alpha-adrenoceptor antagonist, was studied on the perfused ear artery of the rabbit. Yohimbine, 5-hydroxytryptamine (5-HT) and noradrenaline produced concentration-dependent vasoconstriction of the central ear artery and gave EC50 values of 3.5 X 10(-7), 7.5 X 10(-9) and 3.0 X 10(-10) M, respectively. Phentolamine significantly reduced the effects of yohimbine, 5-HT and noradrenaline, and gave pA2 values of 8.40 (slope = 1.0), 8.60 (slope = 0.94) and 8.20 (slope = 1.04), respectively. Methysergide, a serotonergic antagonist, significantly reduced yohimbine- and 5-HT-induced vasoconstriction but failed to influence the effect of noradrenaline. Reserpine treatment induced hypersensitivity of the ear artery to yohimbine and noradrenaline but not to 5-HT. It is suggested that the agonist action of yohimbine on the ear artery may be mediated via activation of alpha-noradrenoceptors.

UI	MeSH Term	Description	Entries
D008784	Methysergide	An ergot derivative that is a congener of LYSERGIC ACID DIETHYLAMIDE. It antagonizes the effects of serotonin in blood vessels and gastrointestinal smooth muscle, but has few of the properties of other ergot alkaloids. Methysergide is used prophylactically in migraine and other vascular headaches and to antagonize serotonin in the carcinoid syndrome.	Dimethylergometrin,Methylmethylergonovine,Deseril,Desril,Désernil-Sandoz,Methysergide Dimaleate,Methysergide Maleate,Sansert,UML-491,Dimaleate, Methysergide,Désernil Sandoz,Maleate, Methysergide,UML 491,UML491
D010646	Phentolamine	A nonselective alpha-adrenergic antagonist. It is used in the treatment of hypertension and hypertensive emergencies, pheochromocytoma, vasospasm of RAYNAUD DISEASE and frostbite, clonidine withdrawal syndrome, impotence, and peripheral vascular disease.	Fentolamin,Phentolamine Mesilate,Phentolamine Mesylate,Phentolamine Methanesulfonate,Phentolamine Mono-hydrochloride,Regitine,Regityn,Rogitine,Z-Max,Mesilate, Phentolamine,Mesylate, Phentolamine,Methanesulfonate, Phentolamine,Mono-hydrochloride, Phentolamine,Phentolamine Mono hydrochloride
D011817	Rabbits	A burrowing plant-eating mammal with hind limbs that are longer than its fore limbs. It belongs to the family Leporidae of the order Lagomorpha, and in contrast to hares, possesses 22 instead of 24 pairs of chromosomes.	Belgian Hare,New Zealand Rabbit,New Zealand Rabbits,New Zealand White Rabbit,Rabbit,Rabbit, Domestic,Chinchilla Rabbits,NZW Rabbits,New Zealand White Rabbits,Oryctolagus cuniculus,Chinchilla Rabbit,Domestic Rabbit,Domestic Rabbits,Hare, Belgian,NZW Rabbit,Rabbit, Chinchilla,Rabbit, NZW,Rabbit, New Zealand,Rabbits, Chinchilla,Rabbits, Domestic,Rabbits, NZW,Rabbits, New Zealand,Zealand Rabbit, New,Zealand Rabbits, New,cuniculus, Oryctolagus
D004432	Ear, Middle	The space and structures directly internal to the TYMPANIC MEMBRANE and external to the inner ear (LABYRINTH). Its major components include the AUDITORY OSSICLES and the EUSTACHIAN TUBE that connects the cavity of middle ear (tympanic cavity) to the upper part of the throat.	Tympanic Cavity,Tympanum,Middle Ear,Cavities, Tympanic,Cavity, Tympanic,Ears, Middle,Middle Ears,Tympanic Cavities,Tympanums
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
D001158	Arteries	The vessels carrying blood away from the heart.	Artery
D015016	Yohimbine	A plant alkaloid with alpha-2-adrenergic blocking activity. Yohimbine has been used as a mydriatic and in the treatment of ERECTILE DYSFUNCTION.	Rauwolscine,Aphrodine Hydrochloride,Aphrodyne,Corynanthine,Corynanthine Tartrate,Pluriviron,Rauhimbine,Yocon,Yohimbin Spiegel,Yohimbine Houdé,Yohimbine Hydrochloride,Yohimex,Hydrochloride, Aphrodine,Hydrochloride, Yohimbine,Tartrate, Corynanthine