Consulta: subjectFacets:"Methylxanthines"
Registros recuperados: 3
Data/hora: 05/06/2024 01:09:24

Caffeine formation by suspension cultures of Coffea dewevrei
Provedor de dados: 52
Autores: Sartor,Rosana Mary; Mazzafera,Paulo.
The low caffeine content in leaves of C. dewevrei (~ 0.5 mg/g) is due to a low biosynthesis associated with a fast degradation. On the other hand, high biosynthesis and low degradation confer a higher content (~ 8 mg/g) in leaves of C. arabica. In this work it was observed that cell cultures of C. dewevrei recovered the ability to synthesize caffeine almost in similar levels of C. arabica cultures. Tracer experiments with labelled carbon dioxide showed a significant accumulation of radioactivity in caffeine and metabolites, indicating an active biosynthesis. When the cultures were fed with labelled caffeine most of the radioactivity was recovered in caffeine, indicating that although active, degradation was not so efficient as in leaves, and therefore,...
Tipo: Info:eu-repo/semantics/article
Palavras-chave: Coffee; Caffeine; Cell suspension culture; Methylxanthines.
Ano: 2000
URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S1516-89132000000100009

Effects of caffeine on learning and memory in rats tested in the Morris water maze
Provedor de dados: 56
Autores: Angelucci,M.E.M.; Cesário,C.; Hiroi,R.H.; Rosalen,P.L.; Cunha,C. Da.
We studied some of the characteristics of the improving effect of the non-specific adenosine receptor antagonist, caffeine, using an animal model of learning and memory. Groups of 12 adult male Wistar rats receiving caffeine (0.3-30 mg/kg, ip, in 0.1 ml/100 g body weight) administered 30 min before training, immediately after training, or 30 min before the test session were tested in the spatial version of the Morris water maze task. Post-training administration of caffeine improved memory retention at the doses of 0.3-10 mg/kg (the rats swam up to 600 cm less to find the platform in the test session, P&lt;=0.05) but not at the dose of 30 mg/kg. Pre-test caffeine administration also caused a small increase in memory retrieval (the escape path of the rats...
Tipo: Info:eu-repo/semantics/article
Palavras-chave: Memory; Learning; Caffeine; Methylxanthines; Adenosine receptor antagonist; Morris water maze.
Ano: 2002
URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S0100-879X2002001000013

Characterization of rat heart alkaline phosphatase isoenzymes and modulation of activity
Provedor de dados: 56
Autores: Mota,A.; Silva,P.; Neves,D.; Lemos,C.; Calhau,C.; Torres,D.; Martel,F.; Fraga,H.; Ribeiro,L.; Alçada,M.N.M.P.; Pinho,M.J.; Negrão,M.R.; Pedrosa,R.; Guerreiro,S.; Guimarães,J.T.; Azevedo,I.; Martins,M.J.
Alkaline phosphatase (ALP) is important in calcification and its expression seems to be associated with the inflammatory process. We investigated the in vitro acute effects of compounds used for the prevention or treatment of cardiovascular diseases on total ALP activity from male Wistar rat heart homogenate. ALP activity was determined by quantifying, at 410 nm, the p-nitrophenol released from p-nitrophenylphosphate (substrate in Tris buffer, pH 10.4). Using specific inhibitors of ALP activity and the reverse transcription-polymerase chain reaction, we showed that the rat heart had high ALP activity (31.73 ± 3.43 nmol p-nitrophenol·mg protein-1·min-1): mainly tissue-nonspecific ALP but also tissue-specific intestinal ALP type II. Both ALP isoenzymes...
Tipo: Info:eu-repo/semantics/article
Palavras-chave: Heart; Alkaline phosphatase; Polyphenol-rich beverages; Steroid hormones; Methylxanthines.
Ano: 2008
URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S0100-879X2008000700009