(n.) An organic base, especially one of a class of substances occurring ready formed in the tissues of plants and the bodies of animals.
Example Sentences:
(1) Thus, alkaloid and insecticide modifications share many features but differ in how much the conducting properties of the pore are changed and whether the channel can close reversibly while the toxin remains bound.
(2) A clear structure-mutagenicity relationship was observed in a series of aporphine alkaloids (aporphine, dehydroaporphine, 7-oxoaporphine and 4,5-dioxoaporphine), and 10,11-non-substituted aporphines were suggested to exert their mutagenicity through metabolic activation of the 10,11 positions, possibly as the 10,11-epoxides.
(3) A radioactive, photoactive Vinca alkaloid, N-(p-azido-[3,5-3H]-benzoyl)-N'-beta-aminoethylvindesine [( 3H]NABV) with pharmacological and biological activities similar to vinblastine was synthesized and used to identify specific Vinca alkaloid macromolecular interactions in calf brain homogenate by photoaffinity labeling.
(4) The comparative metabolism of the pyrrolizidine alkaloid (PA) senecionine was studied in vitro in incubations of rat, guinea pig, cow, horse, and sheep hepatic microsomes.
(5) They also displayed negative correlation between activities of protein-inhibitors and the total content of protein and alkaloids.
(6) Methods have been reviewed for alkylating agents, platinum compounds, antitumour antibiotics, antimetabolites, alkaloids, suramin, 1-hydroxy-3-amino-propylidene-1,1-bisphosphonate and tamoxifen.
(7) The resistant strains exhibited cross resistance to anthracycline antibiotics, vinca alkaloids, actinomycin D, colchicine.
(8) In mice treated with cepharanthine (Cepha), a biscoclaurine alkaloid, the number of T cells was increased in the parathymic lymph nodes (PtLNs) which are considered to be the specialized lymph nodes in local differentiation of T cells.
(9) The alkaloid tubulosine inhibits the process of peptide chain elongation by eukaryotic polysomes by specifically preventing the elongation-factor-2-dependent step of translocation.
(10) Cultured roots of Stephania cepharantha, which are rich sources of bisbenzylisoquinoline alkaloids, were fed 14C-labelled tyrosine, tyramine or dopamine.
(11) As a possible mechanism underlying the alterations of DRP, the functional consequences of atrophic changes of primary central afferent terminals are being discussed in terms of the close correlation between structure and function and the possible inferences of the electrophysiological reaction to the therapeutic application of Vinca alkaloids in the iontophoretic treatment of chronic intractable pain.
(12) The poisonous principles in tansy ragwort are pyrrolizidine alkaloids, which cause gradual alteration and necrosis of liver cells with replacement by fibrous tissue.
(13) In this study, the roots of Tabernaemontana heyneana Wall were examined and the isolation and identification of additional indole alkaloids and some pharmacological properties of coronaridine are described.
(14) The area ratios of four alkaloids (tropacocaine, norcocaine, cis-cinnamoylcocaine, and trans-cinnamoylcocaine) to cocaine are calculated for each sample.
(15) The main drugs with specific action on migraine include ergot alkaloids (ergotamine, dihydroergotamine), agonists (sumatriptan) or partial agonists (methysergide) at a specific subtype of 5-HT1-like receptors, beta-adrenoceptor antagonists (propranolol, metoprolol), calcium antagonists (flunarizine) and anti-inflammatory agents (indomethacin).
(16) Effects of solution variables on the binding and self-association explain the wide variation of reported apparent binding constants for Vinca alkaloids to tubulin.
(17) The concomitance of five previously reported trans-2,5-dialkyl-pyrrolidines along with small amounts of the cis isomers and N-methyl analogues makes the venom of M. indicum the most qualitatively diverse blend of alkaloids reported from an ant to date.
(18) Strong enhancement of delayed-type hypersensitivity (DTH) was observed after treatment with the active cyclophosphamide (CY) derivative Z 7557 or the plant alkaloid VP-16 at the site of sensitization.
(19) A total alkaloid and two purified alkaloid extracts of Alangium Vitiense were revealed by our experimental screening to be oncostatic on L1210 leukemia and two other lymphoid neoplasias in Mice.
(20) Possible mechanisms underlying these effects of insecticides on alkaloid-dependent uptake are discussed in light of a qualitative model formulated from these results and previous biochemical and electrophysiological studies.
Papaverine
Definition:
(n.) An alkaloid found in opium. It has a weaker therapeutic action than morphine.
Example Sentences:
(1) Isoproterenol [IC 50 approximately 1 X 10(-9) M], prostaglandins, dibutyryl cyclic AMP [IC 50 approximately 2 X 10(-5) M], papaverine, theophylline and 5' AMP were inhibitory in the assay, whereas dibutyryl cyclic GMP and the cholinergic stimulator carbamylcholine either stimulated or had no effect on mitosis.
(2) Our work demonstrates that the systemic availability or papaverine can be markedly affected by product formulation.
(3) The amplitude was 15-70% as large as the tonic component of the K-contracture induced by 40 mM K. Theophylline (10 mM), 0.1 mM papaverine and 1 microM isoprenaline nearly abolished, and 1 mM cAMP partly depressed the tonic contraction of K-contracture, whereas the tonic contraction induced by the test solution was unaffected.
(4) In these studies, it is shown that increasing concentrations of carbamylcholine (carbachol) result in a shift to the right of the dose-response curves to (-)-isoproterenol and (-)-soterenol and a reduction of the maximum degree of relaxation produced by these agonists relative to that produced by papaverine.
(5) Similar results were obtained with vincamine (Vi) but vincamine's bronchoconstriction was not completely inhibited by papaverine.
(6) Pressure above and below the stenosis was measured intra-arterially and flow related measurements were made at rest and during reactive hyperaemia in the dog, and following papaverine administration in patients.
(7) Total bacterial counts, nitrate-reducing bacteria and nitrite concentration were determined in fasting gastric juice before and after 4 weeks of treatment with a strong or with a mild antacid drug, a placebo preparation and the spasmolytic agent papaverine which is known to inhibit gastric evacuation.
(8) To assess the role of hydrostatic pressure in edema formation, we compared lung permeability-surface area products (PS) in papaverine-treated lungs given either protamine alone or PAF + protamine and tested the effect of mechanical elevation of Pmv on protamine-induced lung edema.
(9) 50 patients were treated eith carbocromen and 50 with papaverine as controls.
(10) Aminophylline and caffeine can mimic this effect; however, papaverine and 1-methyl-3-isobutylxanthine, at concentrations inhibitory to phosphodiesterase, are without effect on glucocorticoid receptor binding to DNA.
(11) The effects on these kinetics of a joint administration of Papaverine are considered.
(12) The action of papaverine was nearly similar in control and irradiated groups.
(13) In both cell cultures, changes in cyclic nucleotide levels were first observed at 6 h after viral inoculation and were maximal at 12 h. In human fibroblasts, the addition of theophylline, dibutyryl cAMP, or papaverine (cAMP-enhancing compounds) decreased significantly the yield of HSV-1, whereas the addition of insulin or dibutyryl cGMP (cGMP-enhancing compounds) increased the viral yield.
(14) In the presence of 10(-3) M-papaverine higher doses of noradrenaline evoked the non-selective cation current in some portal vein cells.
(15) During constrictions caused by norepinephrine, methylene blue significantly inhibited the renal vasodilatations caused by tertatolol, acetylcholine, papaverine and nitroglycerin but not those caused by atrial natriuretic factor.
(16) The average rates of development of the contractile and relaxation phases and their relative dependence in the acetylcholine contractile effect, after treatment with papaverine, prostaglandines E1 and F2 alpha and BaCl2, are tested on longitudinal and circular smooth muscles of guinea-pig caecum.
(17) A mixture of Hexabrix and papaverine produced a white crystalline precipitate.
(18) Papaverine is useful in vein preparation; it protects the endothelium and smooth muscle cells in the intima and media and prevents leukocyte infiltration and medial fibrosis.
(19) Nifedipine and superoxide dismutase induced small but significant relaxations in phorbol ester-contracted vessels; however, blood vessels contracted with phenylephrine and phorbol ester relaxed completely with papaverine.
(20) Bencyclan (Fludilat), used therapeutically as a vasodilator drug, exerts a distinct negative inotropic and chronotropic action on myocardium, in contrast to papaverine.