PubMed · 14257321
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R W TOFT. CALIBRATING DEVICE FOR TEMPERATURE RECORDING.. https://doi.org/10.1097/00000542-196501000-00018
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A method coupled with microdialysis technique and liquid chromatography was applied in the continuous and concurrent in vivo monitoring of extracellular hesperidin in the blood and bile of anaesthetized rats. Hesperidin was intravenously administered via the femoral vein. Sampling was achieved using two microdialysis probes, which were implanted into the jugular vein and into the bile duct. Dialysates of blood and bile were both directly injected onto the liquid chromatographic system, so no further clean-up procedures were required. Separation was performed using a reversed phase ODS-2 microbore column 150 mm x 1 mm i.d., particle size 5 microm with mobile phase of acetonitrile-0.1M ammonium acetate (30:70, v/v) at flow-rate of 0.05 ml/min. The UV detection for hesperidin was set at a wavelength of 283 nm. This method was used to determine the pharmacokinetics of hesperidin and its interaction in the presence of cyclosporin A, which is a P-glycoprotein modulator. The results indicate that the curve of area under the concentration versus time (AUC) for hesperidin in bile was significantly greater than that for hesperidin in blood at the dose of 30 mg/kg. The blood-to-bile distribution ratio (k = AUC(bile)/AUC(blood)) was 8.9 +/- 2.5 for hesperidin at 30 mg/kg. Following cyclosporin A treatment, the distribution ratio was reduced to 3.2 +/- 0.6. In conclusion, hesperidin goes through hepatobiliary elimination against the concentration gradient from blood to bile, and this hepatobiliary excretion of hesperidin may be regulated by the P-glycoprotein.
To establish a new model of conditioned enhancement of antibody production, electroacupuncture was served as the conditioned stimulus (CS) and an injection of a protein antigen ovalbumin as the unconditioned stimulus (UCS). After a CS/UCS pairing was made, re-exposure of animals to the CS alone resulted in significant conditioned enhancement of anti-ovalbumin antibody production. Even in deep sleep induced by anesthesia, the animals can associate a single CS with UCS and an antibody response can be elicited upon subsequent re-exposure to CS in the absence of exogenous antigen. No effect of electroacupuncture on anti-ovalbumin antibody production was found.
Systemic effects of anesthesia on the dynamics of the apnea-induced Blood Oxygen Level Dependent (BOLD) signal is still not clear. In the present study, the dynamics of the fMRI-BOLD signal and blood flow using laser Doppler flowmetry (LDF) was studied in rats in response to apnea. Two anesthetics namely pentobarbital and urethane, hypothesized to have distinct effects on the mean arterial blood pressure (MAP) were used. During normoxic baseline conditions, MAP decreased in response to apnea in rats anesthetized with pentobarbital but increased with urethane. However, MAP did not change significantly in response to apnea during hyperoxic or hypercapnic baseline conditions with both anesthetics. LDF increased in response to apnea during normoxia, hyperoxia or hypercapnia and was influenced by MAP during normoxia. Apnea-induced BOLD signal dynamics was similar with both anesthetics, dominated by an alteration in arterial blood oxygenation and independent of changes in MAP. Our results suggest that anesthesia-dependent MAP change modulates the apnea-induced cerebral blood flow (CBF) response but has a minimal effect on the fMRI-BOLD signal probably due to uncoupling of CBF and oxygen consumption.