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

To investigate the " drug-guide" effect of Achyranthes bidentata saponins( ABS) and geniposide( GE) in the treatment on adjuvant arthritis( AA) rats. A UHPLC-MS/MS method for the quantitative determination of GE,zingibroside R1,ginsenoside Ro and chikusetsu saponin Ⅳa in rat blood and joint dialysate was established. After single or combined administration with ABS and GE was given to AA rat model,a microdialysis sampling method for rat joint cavity and jugular vein blood vessels was established to collect microdialysis samples. Waters Acquity HSS C_(18) column was used to separate the above four components,with mobile phase as acetonitrile-0. 1% formic acid water as mobile phase for gradient elution. ESI source was adopted for mass spectra in a negative ion scanning mode. Multiple reaction monitoring( MRM) mode was applied to detect the above four components. The methodological results showed that GE,zingibroside R1,ginsenoside Ro and chikusetsu saponin Ⅳa demonstrated a good linear relationship within the concentration ranges of 2-4 000,16-4 096,14-3 584,23-5 888 μg·L-1 respectively. The precision,accuracy,stability and matrix effect of these four ingredients reached the requirements of quantitative analysis of biological samples. The pharmacokinetic results demonstrated that the combined administration of ABS and GE( 60 mg·kg~(-1)+60 mg·kg~(-1)) can increase the degree of GE in joint cavity distribution,and the AUCjoint/AUCplasmwere twice of that of single administration of GE( 60 mg·kg~(-1)),which indicated that ABS might played a vital role in GE's distribution to joint cavity. Moreover,there was no significant difference between the distribution trend of total three ABS and GE in rats. The pharmacodynamics results showed that the combined administration of ABS and GE has stronger effects on paw swelling,arthritis index and synovial pathomorphology of AA rats than single administration of GE,which suggested that ABS might improve GE's anti-inflammatory effect in AA rats. Based on the above results,ABS has a targeting effect in increasing GE's concentration in joint cavity,with a synergy in efficacy.
Achyranthes ; chemistry ; Animals ; Arthritis, Experimental ; drug therapy ; Chromatography, High Pressure Liquid ; Drugs, Chinese Herbal ; pharmacokinetics ; Iridoids ; pharmacokinetics ; Microdialysis ; Rats ; Reproducibility of Results ; Saponins ; pharmacokinetics ; Tandem Mass Spectrometry

Synaptic dopamine (DA) is mainly regulated by the presynaptic DA transporter (DAT). Single-photon emission computerized tomography (SPECT) with the DAT radiotracer [¹²³I]FP-CIT assesses changes in synaptic DA availability when endogenous DA displaces [¹²³I]FP-CIT or competes for DAT. Here, we investigated the effects of haloperidol (HAL) and clozapine (CLZ) on [¹²³I]FP-CIT binding in the rat striatum and midbrain to assess the utility of [¹²³I]FP-CIT SPECT to quantify changes in synaptic DA availability. Rats underwent [¹²³I]FP-CIT SPECT after intraperitoneal administration of normal saline (vehicle), HAL (1 and 7 mg/kg), CLZ (10 and 54 mg/kg) and bupropion (BUP, a DAT blocker, 20 and 100 mg/kg). In the striatum and midbrain, percent differences in the nondisplaceable binding potential (BP(ND)) of [¹²³I]FP-CIT compared to the vehicle were calculated for the various drugs and doses. In another experiment, changes in endogenous striatal DA concentration were measured by in vivo microdialysis under the conditions used in the SPECT study. BUP dose-dependently occupied DAT at considerable levels. Compared to the vehicle, HAL decreased [¹²³I]FP-CIT BP(ND) in the striatum (−25.29% and −2.27% for 1 and 7 mg/kg, respectively) and to a greater degree in the midbrain (−58.74% and −49.64% for 1 and 7 mg/kg, respectively), whereas the CLZ-treated group showed a decrease in the midbrain (−38.60% and −40.38% for 10 and 54 mg/kg, respectively) but an increase in the striatum (18.85% and 38.64% for 10 and 54 mg/kg, respectively). Antipsychotic-induced changes in endogenous striatal DA concentrations varied across drugs and doses. The data demonstrate that [¹²³I]FP-CIT SPECT may be a useful preclinical technique for detecting increases in synaptic DA availability in the midbrain and striatum in response to HAL, with results comparable to those of in vivo microdialysis.
Animals ; Bupropion ; Clozapine ; Dopamine ; Haloperidol ; Mesencephalon ; Microdialysis ; Rats ; Tomography, Emission-Computed, Single-Photon

OBJECTIVE: Globus pallidus interna (GPi) is acknowledged as an essential treatment for advanced Parkinson’s disease (PD). Nonetheless, the neurotransmitter study about its results is undiscovered. The goal of this research was to examine influences of entopeduncular nucleus (EPN) stimulation, identical to human GPi, in no-lesioned (NL) rat and 6-hydroxydopamine (6-HD)-lesioned rat on glutamate change in the striatum.METHODS: Extracellular glutamate level changes in striatum of NL category, NL with deep brain stimulation (DBS) category, 6-HD category, and 6-HD with DBS category were examined using microdialysis and high-pressure liquid chromatography. Tyrosine hydroxylase (TH) immunoreactivities in substantia nigra and striatum of the four categories were also analyzed.RESULTS: Extracellular glutamate levels in the striatum of NL with DBS category and 6-HD with DBS category were significantly increased by EPN stimulation compared to those in the NL category and 6-HD category. EPN stimulation had no significant effect on the expression of TH in NL or 6-HD category.CONCLUSION: Clinical results of GPi DBS are not only limited to direct inhibitory outflow to thalamus. They also include extensive alteration within basal ganglia.
Animals ; Basal Ganglia ; Chromatography, Liquid ; Deep Brain Stimulation ; Entopeduncular Nucleus ; Globus Pallidus ; Glutamates ; Glutamic Acid ; Humans ; Microdialysis ; Neurotransmitter Agents ; Oxidopamine ; Parkinson Disease ; Rats ; Substantia Nigra ; Thalamus ; Tyrosine 3-Monooxygenase

OBJECTIVE: : To analyze experimental factors affecting recovery of puerarin in microdialysis. METHODS: : Puerarin concentration in microdialysate samples was determined by high performance liquid chromatography. The methods of direct dialysis, retrodialysis and the zero-net flux were used to calculate recovery, respectively. The effects of perfusate composition, the analyte concentration, perfusate flow rate, medium temperature and stir rates of the dialysis medium on recovery were investigated. RESULTS: : There were significant differences in the recovery values among direct dialysis, retrodialysis and zero-net flux methods. The recovery for 0.9% NaCl solution, Ringer's solution, PBS and anticoagulant dextrose solution as perfusate fluid were (71.25±2.36)%,(73.48±1.41)%,(68.50±2.43)% and (74.98±1.16)%, respectively. The composition of perfusate fluid had significant influence on the recovery(<0.01). At the same flow rate, recovery was independent of the analyte concentration. At the same concentration, the recovery was decrease with the increasing flow rate in an exponential relationship. The recovery increased with the raising temperature and stir rate of the dialysis medium, and the recovery remained stable when the stir rate reached above 200 rpm. CONCLUSIONS : A study method for recovery of puerarin in microdialysis has been established, and the recovery of puerarin is affected by calculating methods, perfusate fluids, flow rate, medium temperature and stir rate, but not affected by analyte concentrations.
Chemistry Techniques, Analytical ; methods ; Chromatography, High Pressure Liquid ; Isoflavones ; isolation & purification ; Microdialysis

OBJECTIVE: High frequency stimulation (HFS) of the subthalamic nucleus (STN) is recognized as an effective treatment of advanced Parkinson’s disease. However, the neurochemical basis of its effects remains unknown. The aim of this study is to investigate the effects of STN HFS in intact and 6-hydroxydopamine (6-OHDA)-lesioned hemiparkinsonian rat model on changes of principal neurotransmitters, glutamate, and gamma-aminobutyric acid (GABA) in the striatum. METHODS: The authors examined extracellular glutamate and GABA change in the striatum on sham group, 6-OHDA group, and 6-OHDA plus deep brain stimulation (DBS) group using microdialysis methods. RESULTS: High-pressure liquid chromatography was used to quantify glutamate and GABA. The results show that HFS-STN induces a significant increase of extracellular glutamate and GABA in the striatum of 6-OHDA plus DBS group compared with sham and 6-OHDA group. CONCLUSION: Therefore, the clinical results of STN-HFS are not restricted to the direct STN targets but involve widespread adaptive changes within the basal ganglia.
Animals ; Basal Ganglia ; Chromatography, Liquid ; Deep Brain Stimulation ; gamma-Aminobutyric Acid* ; Glutamic Acid* ; Microdialysis ; Models, Animal ; Neurotransmitter Agents ; Oxidopamine ; Parkinson Disease ; Rats* ; Subthalamic Nucleus

BACKGROUND: Nefopam has been known as an inhibitor of the reuptake of monoamines, and the noradrenergic and/or serotonergic system has been focused on as a mechanism of its analgesic action. Here we investigated the role of the spinal dopaminergic neurotransmission in the antinociceptive effect of nefopam administered intravenously or intrathecally. METHODS: The effects of intravenously and intrathecally administered nefopam were examined using the rat formalin test. Then we performed a microdialysis study to confirm the change of extracellular dopamine concentration in the spinal dorsal horn by nefopam. To determine whether the changes of dopamine level are associated with the nefopam analgesia, its mechanism was investigated pharmacologically via pretreatment with sulpiride, a dopaminergic D2 receptor antagonist. RESULTS: When nefopam was administered intravenously the flinching responses in phase I of the formalin test were decreased, but not those in phase II of the formalin test were decreased. Intrathecally injected nefopam reduced the flinching responses in both phases of the formalin test in a dose dependent manner. Microdialysis study revealed a significant increase of the level of dopamine in the spinal cord by intrathecally administered nefopam (about 3.8 fold the baseline value) but not by that administered intravenously. The analgesic effects of intrathecally injected nefopam were not affected by pretreatment with sulpiride, and neither were those of the intravenous nefopam. CONCLUSIONS: Both the intravenously and intrathecally administered nefopam effectively relieved inflammatory pain in rats. Nefopam may act as an inhibitor of dopamine reuptake when delivered into the spinal cord. However, the analgesic mechanism of nefopam may not involve the dopaminergic transmission at the spinal level.
Analgesia ; Animals ; Dopamine ; Microdialysis ; Nefopam* ; Pain Measurement ; Rats* ; Spinal Cord ; Spinal Cord Dorsal Horn ; Sulpiride ; Synaptic Transmission

To establish a method for detecting microdialysis recovery of tetramethylpyrazine (TMP) and ferulic acid (FA) and investigating the influencing factors, providing the basis for further in vivo microdialysis experiments. The concentration of FA and TMP in dialysates were determined by high pressure liquid chromatography ( HPLC) and probe recovery were calculated respectively. The influence of the flow rates, medium concentration, temperature and in vivo probe stability on the recovery of FA and TMP were investigated by using concentration difference method (incremental method and decrement method). The recovery obtained by incremental method were similar to by decrement method. The in vitro recovery rate of FA and TMP decreased with the increase of 1-2.5 μL min(-1), and increased obviously with the temperature of 25-42 degrees C under the same conditions. The concentration of FA and TMP had no obvious effect on the probe recovery under the same flow rate. In addition, the recovery of TMP and FA remained stable and showed similar trends under the condition of four concentration cycles, indicating that the intra day reproducibility of the concentration difference method was good. The recovery of brain microdialysis probes in vivo 8 h maintained a relatively stable, but certain differences existed between different brain microdialysis probes, demonstrating that each probe was required for recovery correction in vivo experiment. Microdialysis sampling can be used for the local brain pharmacokinetic study of FA and TMP, and retrodialysis method can be used in probe recovery of FA and TMP in vivo.
Animals ; Brain ; metabolism ; Chromatography, High Pressure Liquid ; Coumaric Acids ; analysis ; isolation & purification ; pharmacokinetics ; Drugs, Chinese Herbal ; Humans ; Microdialysis ; methods ; Pyrazines ; analysis ; isolation & purification ; pharmacokinetics ; Rats

To detect the in vitro probe microdialysis recoveries based on an HPLC-DAD method for simultaneous quantification of nine active ingredients (ephedrine, pseudoephedrine, methylephedrine, amygdalin, liquiritin, cinnamyl alcohol, cinnamic acid, cinnamaldehyde and glycyrrhizic acid) in Mahuang decoction, which provides reference for in vivo pharmacokinetic study. The concentrations of nine active ingredients in dialysate were detected by HPLC-DAD, to investigate the effect of flow rates (incremental method and subtraction method) and intraday stability of the probe recoveries and medium concentrations on the recoveries. Nine active ingredients could be well separated in 52 min. At the perfusion rate of 1.0 μL x min(-1), the relative recoveries of ephedrine, pseudoephedrine, methylephedrine, amygdalin, liquiritin, cinnamyl alcohol, cinnamic acid, cinnamaldehyde and glycyrrhizic acid were (50.95 ± 0.82)%, (52.74 ± 1.13)%, (51.29 ± 0.51)%, (32.56 ± 0.84)%, (45.36 ± 0.83)%, (70.94 ± 0.99)%, (69.98 ± 2.30)%, (71.68 ± 0.63)%, and (22.14 ± 0.48)%, respectively. And the probe kept steady in 7 hours. At the same medium concentration, the probe recoveries decreased exponentially with the increase in flow rates. The recoveries of seven ingredients detected by these two methods were similar at certain flow rates, except for amygdalin and cinnamaldehyde. At the same flow rate, the relative recoveries of cinnamyl alcohol, cinnamic acid and cinnamaldehyde changed greatly (9.55%-16.2%) and the others six ingredients had less change (3.27%-5.71%) with the changes in medium concentrations. Microdialysis method could be used to detect the in vitro recoveries of nine ingredients in Mahuang decoction. Reverse dialysis method could be used for the in vivo probe recovery calibration of ephedrine, pseudoephedrine, methylephedrine, liquiritin, cinnamyl alcohol and cinnamic acid at the flow rate of 2.0 μL x min(-1).
Chromatography, High Pressure Liquid ; Drugs, Chinese Herbal ; chemistry ; isolation & purification ; Ephedra sinica ; chemistry ; Microdialysis ; methods ; Molecular Structure

Intracellular calcium overload is a key factor for myocardial ischemia reperfusion injury (IR). However, there was no report for interstitial calcium concentration dynamics. We investigated the interstitial calcium dynamics in rat myocardial IR model in vivo. A microdialysis system was involved, and the time delay of the system and recovery time was introduced and tested with a fluids switching method. Twelve SD rats were divided into IR or control group. Myocardial IR was induced by ligating (20 min) then releasing (60 min) the suture underlying left anterior descending branch. Mycrodialyisis probe was implanted into the left ventricular myocardium perfusion area for occlusion. Dialysate samples were collected every 10 min. Dialysate calcium concentration was detected with an atomic absorption spectrophotometer. Recovery time for the microdialysis system was 20 min, and recovery rate was 16%. Dialysate calcium concentration showed no changes during ischemia, descended immediately after reperfusion, reached the lowest level (67% of baseline value) 20 min after reperfusion, then escalated slowly. Recovery time was an important parameter for mycrodialysis technique, and it should not be neglected and needed to be tested. Our data suggest that interstitial calcium concentration in rats with myocardial IR in vivo kept steady in ischemia, descended rapidly at the initial reperfusion, then rebounded slowly. In conclusion, we introduced the concept of recovery time for microdialysis and provided a simple testing method.
Animals ; Calcium ; metabolism ; Dialysis Solutions ; metabolism ; Intracellular Space ; metabolism ; Kinetics ; Male ; Microdialysis ; methods ; Myocardial Reperfusion Injury ; metabolism ; Rats ; Rats, Sprague-Dawley ; Spectrophotometry, Atomic ; Time Factors