Effects of caffeine on learning and memory in rats tested in the Morris water maze

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<=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 was up to 500 cm shorter, P<=0.05). In contrast, pre-training caffeine administration did not alter the performance of the animals either in the training or in the test session. These data provide evidence that caffeine improves memory retention but not memory acquisition, explaining some discrepancies among reports in the literature

Avaliação toxicológica aguda e screening hipocrático da epiisopilosina, alcalóide secundário de Pilocarpus microphyllus Stapf / Toxicological screening failure and the Hippocratic epiisopilosina, alkali secondary Pilocarpus microphyllus Stapf

A espécie Pilocarpus microphyllus Stapf. recebe a designação geral de jaborandi, fonte industrial de pilocarpina, utilizada no tratamento do glaucoma. O jaborandi contém vários alcalóides secundários. A epiisopilosina foi submetida a testes farmacológicos para determinação da DL50’ screening hipocrático e determinação do peso corporal dos animais sobreviventes da DL50. A análise dos resultados revelou que a epiisopilosina apresentou DL50 duas vezes maior que a pilocarpina. Os animais que sobreviveram à determinação da DL50 ganharam peso no período de 14 dias de observação. A eplisopilosina demonstrou ser um estimulante periférico do sistema nervoso parassimpático, semelhante à pilocarpina, somente em altas doses.

Pilocarpus microphyllus Stapf. (Rutaceae) is a source for industrial isolation of pilocarpine, alkaloid used in the treatment of glaucoma. It contains several secondary alkaloids; one of them being eplisopilosine. Pharmacological evaluation showed DL50 value of epiisopilosine two times higher than of pilocarpine. Epiisopilosine also showed to be a pilocarpine-like peripheric stimulant of parasympatic nervous system, although in higher dosis.

Cariogenic [correction of Carcinogenic] potential of a typical cassava flour from the Amazonian region of Brazil.

The purpose of this study was to compare the cariogenic potential of a typical cassava flour (CF) with sucrose and starch, using a severe cariogenic challenge model in rats. Thirty Wistar female pups with their dams (mutans streptococci free) were infected by Streptococcus sobrinus 6715, desalivated when aged 25 days, and placed in a Konig-Hofer programmed feeder at age 26 days. They received 17 meals daily at hourly intervals for 21 days as follows: group (1) powdered plain sucrose and sterile distilled water ad libitum (sdwal); (2) Lf and Sdwal (3) powdered starch and sdwal. Essential nutrition was administered by gavage. Data were analyzed by ANOVA. The percentage of S. Sobrinus related to the total flora and the number of this microorganism were higher in the sucrose and CF groups than starch group. Smooth-surface and [sulcal] caries scores for the groups were: (1) 105.5 [48.0]; (2) 34.1 [39.2]; (3) 10.2 [18.1]. All the groups were statistically significantly different from each other (p < 0.01), although the result for sulcal score for CF was very close to the sucrose group. It is concluded that cassava flour, the main source of carbohydrate for the Amazonian population of Brazil, has moderate cariogenic potential.