No abstract available.
Microdialysis* ; Myocardium*

Liver ; metabolism ; physiopathology ; Microdialysis ; methods

Microdialysis ; Pharmaceutical Preparations ; metabolism ; Pharmacokinetics

No abstract available.
Brain Ischemia* ; Glutamic Acid* ; Microdialysis ; Nitric Oxide Synthase* ; Nitric Oxide*

OBJECTIVE: In general, it is known that repetitive regular stimuli induce tolerance and repetitive irregular stimuli induce sensitization. We sought to determine the dopamine response in the rat prefrontal cortex under the repetitive regular and repetitive irregular stimuli. METHODS: After giving irregular and regular electrical stimuli repetitively to rats, we measured the dopamine levels of prefrontal cortex. We compared these results with the dopamine levels of prefrontal cortex of rats which were given just one electrical stimulus. Samples were obtained using in vivo brain microdialysis. Dopamine levels in the samples were measured by high pressure liquid chromatography with electrochemical detection. RESULTS: 1) Dopamine levels of prefrontal cortex of both repetitive regular stimuli group and repetitive irregular stimuli group increased after electrical stimuli. 2) Dopamine levels of prefrontal cortex also significantly increased after just one electrical stimulus. 3) Among the repetitive regular stimuli group, repetitive irregular stimuli group and one stimulus group, the dopamine response was most significant in the repetitive irregular stimuli group. CONCLUSIONS: Repetitive irregular electrical stimuli induce sensitization of prefrontal cortex and repetitive regular electrical stimuli don't induce tolerance of prefrontal cortex.
Animals ; Brain ; Chromatography, Liquid ; Dopamine* ; Microdialysis ; Prefrontal Cortex* ; Rats*

Microdialysis (MD), as a living bio-sampling technique, can be utilizable in different tissues,organs or different parts of the same organs, in order to clarify the drug's pharmacokinetics, mechanism, and provide a basis for targeting. This article describes a number of points in recent years, the microdialysis technique in pharmacokinetic studies in the field of application of the status and significant progress.
Animals ; Humans ; Microdialysis ; Pharmaceutical Preparations ; analysis ; Pharmacokinetics ; Tissue Distribution

OBJECTIVETo establish the mothod to dectect the microdialysis recovery of HCPT and to investigate the influencing factors, thus to supply experimental basis for in-vivo microdialysis of HCPT.

METHODThe in vitro recovery of HCPT was detected by concentration difference method (increment method and decrement method). The influence of flow rates, medium concentration and temperature on the HCPT recovery and the stability were studied.

RESULTThe recovery detected by increment method was the same as by decrement method. The recovery was independent of HCPT concentrations in the medium. The hydroxycamptothecine recovery had good stability and increased as the temperature rose.

CONCLUSIONMicrodialysis sampling can be used for the pharmacokinetic study of HCPT. Retrodialysis can be used for the determination of the HCPT in vivo recovery.

Metabonomics is the branch of systems biology. It has been widely used in the fields of diagnostic markers discovery, disease prognosis, drug action mechanism, drug efficacy and toxicity evaluation, traditional Chinese medicine syndromes differentiation. There are shortcomings in the conventional metabonomics research. Microdialysis technology is a new type of biosampling technology, and metabonomics research based on microdialysis technology is in the ascendant. In view of the particularity of microdialysis technology and its great differences from traditional sampling and pretreatment methods, the metabonomics process based on microdialysis technology has certain similarities with traditional metabonomics research, and its basic process has some particularity. Advantages and basic strategies of metabonomics research by microdialysis technology are systematically summarized for researchers' reference.
Medicine, Chinese Traditional ; Metabolomics ; Microdialysis ; Research Design ; Systems Biology

We have done a study for the real-time changes of blood-brain-barrier disruption(BBBD) with brain cortical microdialysis induced by intra-carotid mannitol infusion and of cortical blood flow with laser Doppler flowmetry. A microdialysis probe was established on the right parietal cortex with 99mTc-DTPA(500 Da) as a marker, and two laser Doppler probes on the bilateral frontal cortex. Intra-carotid administration of mannitol was followed in 3 rats and intra-arterial infusion of isotonic saline in 3 control rats. Cortical blood flows were increased dramatically by about 270% to 310% from the preinfusion state within 5 minutes after mannitol infusion as compared to an average of 150% increase in saline controls. BBBd-induced extravascular leakage of 99mTc-DTPA sampled by microdialysis and estimated by high pressure liquid chromatography increased dramatically within 2 minutes, maximally about 10 times that of the pre-infusion state within 5-10 minutes after infusion, and decreased rapidly about next 20 minutes but was still more than 4 times the pre-infusion state, and slowed to near preinfusion state during the next 40-60 minutes. This result suggests the real changes of BBBD estimated by brain cortical microdialysis were relatively comparable to previous radioisotope measurement and the first 20 minutes was significantly valuable for administration of certain molecules using BBBD induced by intra-arterial mannitol infusion.
Animals ; Brain ; Chromatography, Liquid ; Hemodynamics ; Infusions, Intra-Arterial ; Laser-Doppler Flowmetry ; Mannitol ; Microdialysis* ; Rabeprazole ; Rats

OBJECT: It is reported that the effect of antipsychotics on the extracellular dopamine levels in the prefrontal cortex is related to the their effect on the negative symptoms. Therefore, we investigated the acute and chronic effects of olanzapine and risperidone on the extracellular dopamine concentrations in the prefrontal cortex of rat. Samples were obtained using in vivo brain microdialysis. METHOD: Dopamine levels in the samples were measured by high pressure liquid chromatography with electrochemical detection. RESULTS: 1) Both the acute treatment of olanzapine and risperidone increased the extracellular dopamine concentrations in the prefrontal cortex, dose-dependently. 2) There was a no significant difference in the maximal change of the extracellular dopamine concentrations in the prefrontal cortex induced by the acute treatment of olanzapine and risperidone. 3) Both the chronic treatment of olanzapine and risperidone also increased the extracellular dopamine concentrations in the prefrontal cortex, but they showed the tolerance effect that the degree of increase was smaller than that of the acute treatment. 4) As for the maximal changes of the extracellular dopamine concentrations in the prefrontal cortex induced by the chronic treatment of olanzapine and risperidone, the effect of the former was greater than that of the latter. CONCLUSION: These results suggest that the effects of olanzapine and risperidone on the negative symptoms are related to the increased extracellular dopamine concentrations in the prefrontal cortex induced by these drugs.
Animals ; Antipsychotic Agents ; Brain ; Chromatography, Liquid ; Dopamine* ; Microdialysis ; Prefrontal Cortex* ; Rats* ; Risperidone*