Biomaterial Database

Allosteric interaction of trimebutine maleate with dihydropyridine binding sites. 1990

M Nagasaki, and H Kurosawa, and K Naito, and H Tamaki

Biological Research Laboratory, Tanabe Seiyaku Co., Ltd., Saitama, Japan.

The effects of trimebutine maleate on [3H]nitrendipine binding to guinea-pig ileal smooth muscle membranes and Ca2(+)-induced contraction of the taenia cecum were studied. Specific binding of [3H]nitrendipine to smooth muscle membranes was saturable, with a KD value and maximum number of binding sites (Bmax) of 0.16 nM and 1070 fmol/mg protein, respectively. Trimebutine inhibited [3H]nitrendipine binding in a concentration-dependent manner with a Ki value of 9.3 microM. In the presence of trimebutine (10 microM), Scatchard analysis indicated a competitive-like inhibition with a decrease in the binding affinity (0.31 nM) without a change in Bmax (1059 fmol/mg protein). However, a dissociation experiment using trimebutine (10 or 100 microM) showed that the decreased affinity was due to an increase of the dissociation rate constant of [3H]nitrendipine binding to the membrane. In mechanical experiments using the taenia cecum, trimebutine (3-30 microM) caused a parallel rightward shift of the dose-response curve for the contractile response to a higher concentration range of Ca2+ under high-K+ conditions in a noncompetitive manner. These results suggest that trimebutine has negative allosteric interactions with 1,4-dihydropyridine binding sites on voltage-dependent Ca2+ channels and antagonizes Ca2+ influx, consequently inhibiting contractions of intestinal smooth muscle.

UI	MeSH Term	Description	Entries
D007082	Ileum	The distal and narrowest portion of the SMALL INTESTINE, between the JEJUNUM and the ILEOCECAL VALVE of the LARGE INTESTINE.
D007700	Kinetics	The rate dynamics in chemical or physical systems.
D008566	Membranes	Thin layers of tissue which cover parts of the body, separate adjacent cavities, or connect adjacent structures.	Membrane Tissue,Membrane,Membrane Tissues,Tissue, Membrane,Tissues, Membrane
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
D009568	Nitrendipine	A calcium channel blocker with marked vasodilator action. It is an effective antihypertensive agent and differs from other calcium channel blockers in that it does not reduce glomerular filtration rate and is mildly natriuretic, rather than sodium retentive.	Balminil,Bay e 5009,Bayotensin,Baypresol,Baypress,Gericin,Jutapress,Nidrel,Niprina,Nitre AbZ,Nitre-Puren,Nitregamma,Nitren 1A Pharma,Nitren Lich,Nitren acis,Nitrend KSK,Nitrendepat,Nitrendi Biochemie,Nitrendidoc,Nitrendimerck,Nitrendipin AL,Nitrendipin Apogepha,Nitrendipin Atid,Nitrendipin Basics,Nitrendipin Heumann,Nitrendipin Jenapharm,Nitrendipin Lindo,Nitrendipin Stada,Nitrendipin beta,Nitrendipin-ratiopharm,Nitrendipino Bayvit,Nitrendipino Ratiopharm,Nitrensal,Nitrepress,Tensogradal,Trendinol,Vastensium,nitrendipin von ct,nitrendipin-corax,Nitre Puren,NitrePuren,Nitrendipin ratiopharm,Nitrendipinratiopharm,nitrendipin corax,nitrendipincorax
D011188	Potassium	An element in the alkali group of metals with an atomic symbol K, atomic number 19, and atomic weight 39.10. It is the chief cation in the intracellular fluid of muscle and other cells. Potassium ion is a strong electrolyte that plays a significant role in the regulation of fluid volume and maintenance of the WATER-ELECTROLYTE BALANCE.
D002118	Calcium	A basic element found in nearly all tissues. It is a member of the alkaline earth family of metals with the atomic symbol Ca, atomic number 20, and atomic weight 40. Calcium is the most abundant mineral in the body and combines with phosphorus to form calcium phosphate in the bones and teeth. It is essential for the normal functioning of nerves and muscles and plays a role in blood coagulation (as factor IV) and in many enzymatic processes.	Coagulation Factor IV,Factor IV,Blood Coagulation Factor IV,Calcium-40,Calcium 40,Factor IV, Coagulation
D002432	Cecum	The blind sac or outpouching area of the LARGE INTESTINE that is below the entrance of the SMALL INTESTINE. It has a worm-like extension, the vermiform APPENDIX.	Cecums
D004095	Dihydropyridines	Pyridine moieties which are partially saturated by the addition of two hydrogen atoms in any position.