(n.) A white, bitter, crystallizable substance, obtained from coffee. It is identical with the alkaloid theine from tea leaves, and with guaranine from guarana.
Example Sentences:
(1) Blood was collected from pups and dams to determine its caffeine concentration.
(2) When caffeine evokes a contraction, and only then, crayfish muscle fibers become refractory to a second challenge with caffeine for up to 20 min in the standard saline (5 mM K(o)).
(3) As expected, chronic administration led to complete tolerance to caffeine's locomotor stimulant effect, while subchronic administration produced sensitization.
(4) Caffeine and 6-methylaminopurine riboside (6-N-methyladenosine differentially inhibit uptake of radioactivity from adenosine and inosine, and thus the vesicles apparently possess seperate transport systems for uptake of radioactivity from purine nucleosides and from uridine.
(5) The inositol 1,4,5-trisphosphate (IP3) binding inhibitor, heparin, has no effect on ryanodine binding, and ryanodine and caffeine do not influence the binding of [3H]IP3, which is enriched in the cerebellar fractions.
(6) Post-labeling addition of 1 mM caffeine increased perpetuated blocks to a frequency of about 10% of the initial number of dimers in 4 h in XP16KO-II cells, but not in XP16KO-I and normal cells.
(7) Thus, in human lymphocytes the frequencies of chromatid aberrations induced by most clastogenic agents were strongly enhanced when caffeine was given during the G2 phase, but little affected by post-treatments with caffeine during the S phase.
(8) The Na(+)-induced Ca++ release from the sarcolemmal vesicles was stimulated with caffeine in a concentration-dependent manner; about 80% increase in the activity was observed at 0.1 mM caffeine.
(9) All other dietary constituents, such as protein, fiber, fluid, minerals (including Ca, Mg, Na, K, and P), and caffeine intake, were kept constant.
(10) All calcium, magnesium, and zinc contents per bone decreased in the 1- and 2-mg caffeine groups as compared to either controls or 0.5-mg caffeine group, whereas phosphorus stayed relatively constant regardless of the different levels of caffeine intake.
(11) In the presence of agents that inhibit sarcoplasmic reticulum (SR) function (10 mM caffeine, 100-500 nM ryanodine), reduction of the [Na] gradient produced increases in contractile force similar to that observed in the absence of caffeine or ryanodine.
(12) On the basis of these findings, it is suggested that screening for malignant hyperpyrexia by in vitro pharmacological testing of skeletal muscle should be carried out at 37 degrees C, and should include exposure of the sample to halothane, caffeine, suxamethonium and potassium rather than to halothane alone.
(13) The mechanism responsible for the potentiated anti-inflammatory and mild analgesic activity of aspirin remains unknown since caffeine did not alter the plasma salicylate levels or prostaglandin synthetase inhibition produced by aspirin.
(14) Their pups continued to consume the caffeine diet until 50 days.
(15) The pups were divided into caffeine and noncaffeine groups.
(16) In this study, eight patients participated in a standardized protocol to assess the effects of caffeine on seizures in ECT.
(17) These patients may have an increased risk of cardiovascular and cerebral excitation associated with higher concentrations of caffeine, which could complicate withdrawal from alcohol.
(18) were elevated significantly (P less than 0.05 at 0.3, 0.6 and 1 h after injection) when caffeine 5 or 10 mg kg-1 i.v.
(19) This study supports the findings of others in that caffeine restriction is an effective means of management of breast pain associated with fibrocystic disease.
(20) 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.
Stimulant
Definition:
(a.) Serving to stimulate.
(a.) Produced increased vital action in the organism, or in any of its parts.
(n.) That which stimulates, provokes, or excites.
(n.) An agent which produces a temporary increase of vital activity in the organism, or in any of its parts; -- sometimes used without qualification to signify an alcoholic beverage used as a stimulant.
Example Sentences:
(1) Stimulation of human leukocytes with various chemical mediators such as TPA, f-Met-Leu-Phe, LTB4, etc.
(2) The optimal size for stimulation was between 5 degrees and 12 degrees (visual angle).
(3) After stimulation with lipopolysaccharide and calcium ionophore A23187, culture supernatants of clones c18A and c29A showed cytotoxic activity against human melanoma A375 Met-Mix and other cell lines which were resistant to the tumor necrosis factor, lymphotoxin and interleukin 1.
(4) Apparently, the irradiation with visible light of a low intensity creates an additional proton gradient and thus stimulates a new replication and division cycle in the population of cells whose membranes do not have delta pH necessary for the initiation of these processes.
(5) In conclusion, in S-rats a glucose-stimulated insulin release is accompanied by an increase in IBF, but this is not observed in P-rats.
(6) Stimulation is also observed with mixtures of APC expressing DPw3 and APC expressing A1, and likewise, DPw3+ APC become stimulatory when preincubated with supernatants from A1-positive cells.
(7) We have previously shown that serotonin is present in secretory granules of frog adrenochromaffin cells; concurrently, we have demonstrated that serotonin is a potent stimulator of corticosterone and aldosterone secretion by adrenocortical cells.
(8) Cyclic AMP stimulated phosphorylation by [gamma-32P]ATP of two proteins of apparent Mr = 20,000 and 7,000 that were concentrated in sarcoplasmic reticulum, but the stimulation was markedly dependent on the presence of added soluble cyclic AMP-dependent protein kinase.
(9) We have investigated a physiological role of endogenous insulin on exocrine pancreatic secretion stimulated by a liquid meal as well as exogenous secretin and cholecystokinin octapeptide (CCK-8) in conscious rats.
(10) Whether hen's egg yolk can be used as a sperm motility stimulant in the treatment of such conditions as asthenospermia and oligospermia is subjected for further study.
(11) Some of those drugs are able to stimulate the macrophages, even in an aspecific way, via the gut associated lymphatic tissue (GALT), that is in connection with the bronchial associated lymphatic tissue (BALT).
(12) The results also suggest that the dispersed condition of pigment in the melanophores represents the "resting state" of the melanophores when they are under no stimulation.
(13) dl-Methionine stimulated the synthesis of cephalosporins when added after the growth phase.
(14) Bradykinin also stimulated arachidonic acid release in decidual fibroblasts, an effect which was potentiated in the presence of epidermal growth factor (EGF), but which was not accompanied by an increase in PGF2 alpha production.
(15) Pokeweed mitogen-stimulated rat spleen cells were identified as a reliable source of rat burst-promoting activity (PBA), which permitted development of a reproducible assay for rat bone marrow erythroid burst-forming units (BFU-E).
(16) To investigate the mechanism of enhanced responsiveness of cholesterol-enriched human platelets, we compared stimulation by surface-membrane-receptor (thrombin) and post-receptor (AlF4-) G-protein-directed pathways.
(17) Estimates of potential for gastrointestinal side effects using the rat enteropooling assay and in vivo monkey effects indicate that diarrhea will be substantially reduced with retention of uterine stimulating potency.
(18) Because it has been suggested that the lathyrogen, BAPN, may stimulate the release of proteases, the protease inhibitors Trasylol and epsilon-aminocaproic acid (EACA) were given alone or in combination to BAPN-treated rats.
(19) The present study was designed to test the hypothesis that the decreased Epi response following ET was due to 1) depletion of adrenal Epi content such that adrenomedullary stimulation would not release Epi, 2) decreased Epi release with direct stimulation, i.e., desensitization of release, or 3) decreased afferent signals generated by ET itself.
(20) Stimulation of atrial H1-receptors is suggested to directly cause an increase in Ca-channel conductance independent of intracellular cAMP content.