(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.
Strychnine
Definition:
(n.) A very poisonous alkaloid resembling brucine, obtained from various species of plants, especially from species of Loganiaceae, as from the seeds of the St. Ignatius bean (Strychnos Ignatia) and from nux vomica. It is obtained as a white crystalline substance, having a very bitter acrid taste, and is employed in medicine (chiefly in the form of the sulphate) as a powerful neurotic stimulant. Called also strychnia, and formerly strychnina.
Example Sentences:
(1) The in vitro metabolism of strychnine was studied in the 9000g supernatant fractions from rat and rabbit livers.
(2) 5 alpha-Pregnan-3 alpha-ol-20-one protected mice against metrazol-, bicuculline- and picrotoxin-induced seizures but not against electroshock-and strychnine-induced seizures.
(3) Pre-treatment with subconvulsive doses of strychnine, an antagonist of the neurotransmitter glycine, partially or completely blocked the inhibitory effects on phrenic activity of muscle-afferent stimulation.
(4) From a comparison of activation by strychnine and picrotoxin in normal and chronically decapitated embryos it was deduced that a spinal and a supraspinal component participated in their effect.
(5) Injections of glycine or strychnine (10--100 micrograms) into one SN induced slow ipsiversive or contraversive turning respectively.
(6) alpha-Bungarotoxin (10(-7) M), decamethonium (10(-5) M), d-tubocurarine (5 X 10(-5) M), and strychnine (5 X 10(-5) M) blocked the carbachol depolarization by about 90%.
(7) The action of strychnine and picrotoxin on the values of different reflex components was not identical; this pointed to a different localization of the inhibitory action of GABA and glycine in the central link of the somatosympathetic reflex arch.
(8) The inhibitory effect of bicuculline and strychnine was accompanied by vigorous convulsions.
(9) To determine whether the inhibitory neurotransmitter, glycine, contributes to the action of VS, strychnine, a specific glycine receptor antagonist was administered perispinally via intrathecal catheter in dosages of 1,5,25 and 100 micrograms.
(10) These findings demonstrate that strychnine-induced motor evoked potential changes arise from spinal gray activity induced by efferent pathways activated during transcortical stimulation.
(11) With strychnine, specific antagonist of glycine, excitation prevailed in EI, I and E neurons.
(12) While NAL and OXO did not alter the threshold for convulsions induced by PTZ, strychnine or picrotoxin, both agents lowered the threshold for electroshock-induced seizures.
(13) The intracisternal injection of HEPB or gamma-aminobutyric acid (GABA) in mice resulted in a potentiation of strychnine-induced convulsions.
(14) The effect of equimolar doses of glycine (G) and some related amino acids: beta-alanine (A), taurine (T) and betaine (B) on the strychnine syndrome was tested by administering them (intrathecal route) along with strychnine.
(15) MDL 27,531, which acts functionally like a glycine agonist in its capacity to selectively reverse seizures produced by the glycine antagonist strychnine, was evaluated in a model of spinal injury-induced reflex dysfunction.
(16) Strychnine blockade was also reversed by Cdp (10 micrometer).
(17) A focus of more powerful excitation created with the same strychnine played the role of determinant despatch station (DDS).
(18) The efflux of taurine was unaffected by strychnine, picrotoxin, tubocurarine, atropine, chlorpromazine, and 2-amino-4-phosphonobutyrate, whereas it was increased by glutamate diethyl esther and alpha-amino adipate.
(19) Some neurones failed to demonstrate this behaviour following the administration of strychnine.
(20) Strychnine improved the patient's motoricity presumably by blocking the excessive glycine-mediated inhibition of motoneurons.