Intensity of schistosoma mansoni infection determines alterations in hepatic drug metabolism

Zoxazolamine paralysis times have been used as a probe to measure the activity of cytochrome P450 1A1 in mice in vivo. The results indicated that male and female mice of the BALB/c and CBA/J strain did not show altered paralysis times if infected with less than 4 worm pairs. Alterations were observed only in animals harboring more than 5 worm pairs, irrespective of sex or strain of mouse being used. The study has extended the findings of other workers showing that mice infected with fewer than 4-5 worm pairs of S. mansoni do not show any alteration in the metabolism of pentobarbital in vivo

Effect of beta-myrcene on pentobarbital sleeping time

Evidence that beta-myrcene (MYR) interferes with the metabolic activation of premutagens has been provided by in vitro studies. In order to determine whether MYR also interferes with the in vivo metabolism of xenobiotics, thereby modifying pharmacological responses to drugs, we investigated the effects of this monoterpene on pentobarbital (PT) sleeping time in rats. Two experiments were carried out. In the first, a single dose of MYR (0.25, 0.5 or 1.0 g/kg po) was given 1 h before PT (40 mg/kg ip). No effect was observed with the two lowest doses, but the highest MYR dose given 1 h before PT increased the PT-induced sleeping time (131 +/- 15 min vs 64 +/- 15 min for controls, mean +/- SD). In the second experiment, male rats were treated with MYR (1.0 g/kg po once a day) for 14 days and injected with PT (40 mg/kg ip) 24 h after the last dose of MYR. Repeated treatment with MYR markedly reduced PT sleeping time compared to the vehicle-treated control group (21 +/- 13 min vs 35 +/- 19 min for controls, mean +/- SD). These results indicate that MYR interferes with the in vivo barbiturate metabolism and support the view that MYR induces the phenobarbital-inducible cytochrome P-450 (P-450 2B subfamily) enzymes in the rat