Biomaterial Database

[Blocking actions of l-stephanine, xylopine and 7 other tetrahydroisoquinoline alkaloids on alpha adrenoceptors]. 1989

G Q Liu, and B Y Han, and E H Wang

The blocking action and selectivity of 9 tetrahydroisoquinoline alkaloids on alpha adrenoceptors have been investigated in isolated tissues. Dehydrostephanine and berbamine suppressed the inhibition of clonidine for the electrically stimulated twitch response of rat vas deferens, with pA2 values of 5.36 and 5.49, respectively. l-Crebanine, l-tetrahydrocoptisine, berberine, l-stepholidine and l-tetrahydropalmatine had obvious blocking effects on alpha 1 and alpha 2 adrenoceptors. l-Stephanine and xylopine could competitively inhibit anococcygeus muscle contraction induced by phenylephrine with pA2 values of 6.76 and 6.68, respectively. These 2 alkaloids showed no effect on the inhibition of clonidine for contractile response of rat vas deferens to field stimulation, and their selectivity ratios to block alpha 1 and alpha 2 adrenoceptors were 57.5 and 47.9, respectively. These results indicate that l-stephanine and xylopine are 2 potent and highly selective alpha 1 adrenoceptor blockers.

UI	MeSH Term	Description	Entries
D007546	Isoquinolines	A group of compounds with the heterocyclic ring structure of benzo(c)pyridine. The ring structure is characteristic of the group of opium alkaloids such as papaverine. (From Stedman, 25th ed)
D008297	Male		Males
D009119	Muscle Contraction	A process leading to shortening and/or development of tension in muscle tissue. Muscle contraction occurs by a sliding filament mechanism whereby actin filaments slide inward among the myosin filaments.	Inotropism,Muscular Contraction,Contraction, Muscle,Contraction, Muscular,Contractions, Muscle,Contractions, Muscular,Inotropisms,Muscle Contractions,Muscular Contractions
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
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
D005260	Female		Females
D000317	Adrenergic alpha-Antagonists	Drugs that bind to but do not activate alpha-adrenergic receptors thereby blocking the actions of endogenous or exogenous adrenergic agonists. Adrenergic alpha-antagonists are used in the treatment of hypertension, vasospasm, peripheral vascular disease, shock, and pheochromocytoma.	Adrenergic alpha-Receptor Blockaders,alpha-Adrenergic Blocking Agents,alpha-Adrenergic Receptor Blockaders,alpha-Blockers, Adrenergic,Adrenergic alpha-Blockers,alpha-Adrenergic Antagonists,alpha-Adrenergic Blockers,Adrenergic alpha Antagonists,Adrenergic alpha Blockers,Adrenergic alpha Receptor Blockaders,Agents, alpha-Adrenergic Blocking,Antagonists, alpha-Adrenergic,Blockaders, Adrenergic alpha-Receptor,Blockaders, alpha-Adrenergic Receptor,Blockers, alpha-Adrenergic,Blocking Agents, alpha-Adrenergic,Receptor Blockaders, alpha-Adrenergic,alpha Adrenergic Antagonists,alpha Adrenergic Blockers,alpha Adrenergic Blocking Agents,alpha Adrenergic Receptor Blockaders,alpha Blockers, Adrenergic,alpha-Antagonists, Adrenergic,alpha-Receptor Blockaders, Adrenergic
D000470	Alkaloids	Organic nitrogenous bases. Many alkaloids of medical importance occur in the animal and vegetable kingdoms, and some have been synthesized. (Grant & Hackh's Chemical Dictionary, 5th ed)	Alkaloid,Plant Alkaloid,Plant Alkaloids,Alkaloid, Plant,Alkaloids, Plant
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
D001003	Anal Canal	The terminal segment of the LARGE INTESTINE, beginning from the ampulla of the RECTUM and ending at the anus.	Anal Gland, Human,Anal Sphincter,Anus,Anal Gland,Anal Glands, Human,Detrusor External Sphincter,External Anal Sphincter,Internal Anal Sphincter,Anal Sphincter, External,Anal Sphincter, Internal,Anal Sphincters,Detrusor External Sphincters,External Anal Sphincters,Human Anal Gland,Human Anal Glands,Internal Anal Sphincters,Sphincter, Anal,Sphincter, Detrusor External,Sphincter, External Anal,Sphincter, Internal Anal,Sphincters, Anal