Biomaterial Database

The effect of nifedipine on the contractile responses of the longitudinal and circular muscle of the isolated guinea-pig ileum to various agonists. 1987

L Grbović, and B Z Radmanović

Department of Pharmacology, Medical Faculty, Belgrade, Yugoslavia.

We investigated the inhibitory effect of nifedipine on contractile responses of the longitudinal and circular muscle of the isolated guinea-pig ileum. Nifedipine in very low concentrations, ranging from picomolar to nanomolar, inhibits the phasic and the tonic contractile responses of the longitudinal muscle induced by various agonists (histamine, acetylcholine, prostaglandin E2, serotonin and potassium chloride) in a concentration-dependent manner. Nifedipine produces a stronger inhibition of the tonic than of the phasic component of contractions induced by used spasmogens. The tonic contractile responses evoked by histamine and acetylcholine exhibited the highest degree of sensitivity to the inhibitory action of nifedipine. The calculated values of mean effective concentrations (ED50) indicate that the phasic responses of agonists are less sensitive to nifedipine. For obtaining a similar degree of inhibition of phasic contractions much higher concentrations of nifedipine are necessary. Our findings that nifedipine inhibits more strongly the tonic than the phasic contractile responses produced by different agonists, support the hypothesis of the existence of various types of calcium channels in the guinea-pig longitudinal muscle. Also, nifedipine reduced the contractile responses of the ileal circular muscle induced by histamine, acetylcholine, prostaglandin E2, serotonin and potassium chloride, in a concentration-dependent manner. The contractions induced by histamine are most sensitive to the inhibitory action of nifedipine. It should be pointed out that the phasic responses of the longitudinal muscle and contractions of the circular muscle are approximately equally sensitive to nifedipine. It can be speculated that some inherent similarity exists in contractile processes of the phasic responses of the longitudinal muscle and contractions of the circular muscle, or that agonists act via the same (or similar) population of calcium channels. Enhancing the calcium concentration in the bathing fluid did not reverse the inhibitory effect of nifedipine on contractions of the longitudinal and circular muscle, induced by various agonists.

UI	MeSH Term	Description	Entries
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
D009543	Nifedipine	A potent vasodilator agent with calcium antagonistic action. It is a useful anti-anginal agent that also lowers blood pressure.	Adalat,BAY-a-1040,Bay-1040,Cordipin,Cordipine,Corinfar,Fenigidin,Korinfar,Nifangin,Nifedipine Monohydrochloride,Nifedipine-GTIS,Procardia,Procardia XL,Vascard,BAY a 1040,BAYa1040,Bay 1040,Bay1040,Monohydrochloride, Nifedipine,Nifedipine GTIS
D011189	Potassium Chloride	A white crystal or crystalline powder used in BUFFERS; FERTILIZERS; and EXPLOSIVES. It can be used to replenish ELECTROLYTES and restore WATER-ELECTROLYTE BALANCE in treating HYPOKALEMIA.	Slow-K,Chloride, Potassium
D011458	Prostaglandins E	(11 alpha,13E,15S)-11,15-Dihydroxy-9-oxoprost-13-en-1-oic acid (PGE(1)); (5Z,11 alpha,13E,15S)-11,15-dihydroxy-9-oxoprosta-5,13-dien-1-oic acid (PGE(2)); and (5Z,11 alpha,13E,15S,17Z)-11,15-dihydroxy-9-oxoprosta-5,13,17-trien-1-oic acid (PGE(3)). Three of the six naturally occurring prostaglandins. They are considered primary in that no one is derived from another in living organisms. Originally isolated from sheep seminal fluid and vesicles, they are found in many organs and tissues and play a major role in mediating various physiological activities.	PGE
D005260	Female		Females
D006168	Guinea Pigs	A common name used for the genus Cavia. The most common species is Cavia porcellus which is the domesticated guinea pig used for pets and biomedical research.	Cavia,Cavia porcellus,Guinea Pig,Pig, Guinea,Pigs, Guinea
D006633	Histamine Antagonists	Drugs that bind to but do not activate histamine receptors, thereby blocking the actions of histamine or histamine agonists. Classical antihistaminics block the histamine H1 receptors only.	Antihistamine,Antihistamines,Histamine Antagonist,Antagonist, Histamine,Antagonists, Histamine
D000109	Acetylcholine	A neurotransmitter found at neuromuscular junctions, autonomic ganglia, parasympathetic effector junctions, a subset of sympathetic effector junctions, and at many sites in the central nervous system.	2-(Acetyloxy)-N,N,N-trimethylethanaminium,Acetilcolina Cusi,Acetylcholine Bromide,Acetylcholine Chloride,Acetylcholine Fluoride,Acetylcholine Hydroxide,Acetylcholine Iodide,Acetylcholine L-Tartrate,Acetylcholine Perchlorate,Acetylcholine Picrate,Acetylcholine Picrate (1:1),Acetylcholine Sulfate (1:1),Bromoacetylcholine,Chloroacetylcholine,Miochol,Acetylcholine L Tartrate,Bromide, Acetylcholine,Cusi, Acetilcolina,Fluoride, Acetylcholine,Hydroxide, Acetylcholine,Iodide, Acetylcholine,L-Tartrate, Acetylcholine,Perchlorate, Acetylcholine