Microdialysis—Theory and application

Benveniste, Helene; Hüttemeier, Peter C.

doi:10.1016/0301-0082(90)90027-e

Cited by 622 publications

(280 citation statements)

References 184 publications

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“…It has always been as sumed that the relative recovery of a substance is independent of its outer concentration (Benveniste and Hiittemeier, 1990). However, we have consis tently found that this is not the case with Cys and GSH in vitro at concentrations between 2,500 and 20,000 nM.…”

Section: Resultsmentioning

confidence: 49%

“…It is possible that the thiol groups interact with the dialysis membrane via an unknown mechanism, as has been reported for other transported substances (Benveniste and Hiit temeier, 1990). Although it is known that in vivo recovery for some substances is lower than in vitro (Benveniste and Hiittemeier, 1990), we can esti mate from Table 1 that the basal concentrations of Cys and GSH in the dialysate (40 nM) must be at least 3,000 nM in the EC fluid. After MCAO, GSH showed an immediate in crease in concentration in the microdialysate, to a maximal value of 644 nM at 0.5 h (Table 2).…”

Section: Resultsmentioning

confidence: 89%

“…As we found that the recoveries of GSH and Cys were dependent on the concentration of the outer medium, they were measured in vitro using a range of concentrations comparable to that in vivo. To avoid changes of relative recovery with time during the first 30 min (Benveniste and Hiittemeier, 1990), the microdialysis probe was perfused in the corresponding outer medium for 30-60 min before starting measurement.…”

Section: Microdialysismentioning

confidence: 99%

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Extracellular Antioxidants and Amino Acids in the Cortex of the Rat: Monitoring by Microdialysis of Early Ischemic Changes

Landolt

Lutz²,

Langemann³

et al. 1992

J Cereb Blood Flow Metab

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Summary: Extracellular concentrations of ascorbic acid, glutathione, cysteine, uric acid, tyrosine, and tryptophan were monitored using intracerebral microdialysis in the left frontoparietal cortex of spontaneous hypertensive rats before, and for 3 h after, either focal ischemia [left middle cerebral artery occlusion (MCAO)] or sham oper ation. The size of the ischemic area and the position of the microdialysis probe were checked using the enzyme his totopochemical acid phosphatase reaction. The probe was always located in the cortex inside the stained area. Ascorbic acid levels rose immediately after MCAO and remained at about 12-fold for 3 h. There was a transient Microdialysis (Tossman and V ngerstedt, 1986; Benveniste and Huttemeier, 1990) provides a mini mally invasive method for continuously monitoring changes in concentrations of low-molecular-weight substances in the extracellular (EC) fluid of various organs. It has been used to study cerebral ischemia in the rat, measurements being made mainly in the striatum, one of the areas most susceptible to isch emic damage. Changes have been found in this re gion at the onset of cerebral ischemia in the EC concentrations of various parameters, e. g. , ascor bic acid (Hillered et aI. , 1988), lactate (Hillered et aI., 1989), purine metabolites (Hagberg et aI. , 1987),

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Section: Resultsmentioning

confidence: 49%

Section: Resultsmentioning

confidence: 89%

Section: Microdialysismentioning

confidence: 99%

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Extracellular Antioxidants and Amino Acids in the Cortex of the Rat: Monitoring by Microdialysis of Early Ischemic Changes

Landolt

Lutz²,

Langemann³

et al. 1992

J Cereb Blood Flow Metab

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“…Baseline levels were the mean of the last three samples before drug injection. The probes had an in vitro recovery of 10-12% for dopamine, but the reported concentrations (pg/50 ¡i\ of dialysate) were not adjusted for recovery in vivo because these estimations are inaccu rate (Benveniste et al, 1989;Benveniste and Huttemeier, 1990;Lindefors et al, 1989). Contralateral turnings (de fined as complete 360° turns) were counted visually by a trained observer who had no prior knowledge of the drug treatment.…”

Section: 1 Animals and Surgerymentioning

confidence: 99%

Stimulation of acetylcholine or dopamine receptors in the nucleus accumbens differentially alters dopamine release in the striatum of freely moving rats

Koshikawa

Yoshida

Kitamura

et al. 1996

European Journal of Pharmacology

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The present study examined whether unilateral stimulation of acetylcholine or dopamine receptors in the nucleus accumbens induces an asymmetry in dopamine transmission in the ventrolateral striatum. For this purpose, a microdialysis technique was used to measure dopamine release in both sides of the ventrolateral striatum following unilateral injections of carbachol (5 ¿¿g/0.5 j j l \ ) or a mixture of dopamine Dj and dopamine D 2 receptor agonists (l-phenyl-2,3,4,5-tetrahydro-ltf-3-benzazepine-7,8-diol 5 fig + quinpirole 10 ¿¿g/0.5 /xl) into the nucleus accumbens. The results show that carbachol injection increased dopamine release in the ipsilateral striatum without changing dopamine release in the contralateral striatum, whereas the dopamine D , / D 2 receptor agonist mixture injected unilaterally into the nucleus accumbens produced an increase followed by a decrease in dopamine release in the ipsilateral striatum, but only a decrease in dopamine release in the contralateral striatum. The biochemical effects of the cholinergic treatment greatly outlasted the drug-induced contralateral turning, whereas the biochemical effects of the dopaminergic treatment showed a good correlation with the drug-induced contralateral turning. The present study provides biochemical evidence that unilateral stimulation of acetylcholine or dopamine receptors in the nucleus accumbens elicits an asymmetry in dopaminergic activity in the ventrolateral striatum. The present study also provides biochemical evidence that two distinct neural substrates are involved in the effects of cholinergic and dopaminergic manipulation of the nucleus accumbens.

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“…The spectral and temporal resolution is sufficiently good to follow rapid processes, and may allow the in vivo study of neurological disorders affecting neurotransmitters. (1990) . .iP…”

Section: Bcsultsmentioning

confidence: 99%

Abstracts-part I (Continue in Part II)

1991

Proc. Soc. Magn. Reson. Med.

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In the isolated heart, global, total ischemia is a zero flow-, low intracellular pH (pHi)-, zero workload-, zero substrate-, zero oxygen-and high intracellular Ca+ + (Cai)-situation. High-KCI cardioplegia dose-dependently decreases the membrane potential (AE) leading to Caioverload due to opening of Ca++-channels. Thus, high-KCI cardioplegia should allow isolation of the high Cai and zero-workload aspects of ischemic injury, while flow, pHi, substrate and oxygen delivery remain normal or close to normal. Purpose of this study was to define membrane potential-dependent changes of cardiac performance and Mgh-energy phosphate metabolism evoked by varying AE from normal (-90) to depolarized levels of -6 mV.Furthermore, we followed hearts during recovery (repolarization) following depolarization.Isolated rat hearts were perfused with phosphate-free glucose-containing (1 1 mM) oxygenated (95%02. 5%&02) Krebs-Henseleit (KH) buffer at 37 OC using a constant flow of 24+2 mllmin adjusted to yield a coronary perfusion pressure of 100 mmHg. Performance (LV balloon) was calculated as the rate-pressure product (RPP; IOammHglmin). On a Bruker 7 T MR system, 31P-NMR spectra were recorded at 7 min intervals by signalaveraging 210 FlDs using a pulse angle of 45 0 and a req@e time of 1.93 sec; spectra were corrected for partial saturation. Hearts (n=5 per group) were subjected to 21 min of Control (KCI=4.7 mM) perfusion, 56 min of high-KCI ([KCI] 30, 70, 90 or 110 mM) and 49 min of reeovery at normal (4.7 mM) KCI (Re-KH). According to the Nernst equation (AE = -RT/ZKF In KilKo'), AE was calculated to be -90, -40, -18, -11 and - Figure 1 shows typical spectra of a heart during control, at the end of low-AE (-6 mV) and at the end of recovery. Mean values are given in Figure 2 (ATP) and in the Table. Cardiac contractions immediately ceased at all low-AEs. During Re-KH, RPP recovered to 76f4, 68*10, 44k5 and 27f3 % of control after -40, -18, -11 and -6 mV, resp.; end-diastolic pressure (EDP; set to 10 mmHg during control) increased to 36k7, 33M, 50k6 and 80k6 at the end of low-AE and decreased to 11k2, 12f1, 21+2 and 49f9 mmHg at the end of Re-KH, resp. Thus, during Re-KH, mechanical recovery was inversely correlated to AE during injury. 40 mV did not deplete ATP (mM) or creatine phosphate (CP; mM). For the lower AE, ATP and CP decreased monotonically during cardioplegia with the rate of decline depending on AE; during Re-KH, ATP did not increase; CP showed some recovery but remained significantly depressed; inorganic phosphate (Pi; mM) increased under -18, -11 and -6 mV, but not under -40 mV. Due to high coronary flow, pHi showed only minor changes (0.18 pH units at most); however, there was a slight increase with -40 and -18 and a slight decrease with -6 mV; both effects were reversible with Re-KH.12 - -8Lowering AE by high-KCI cardioplegia causes depletion of high-energy phosphates and reduced post-cardioplegic systolic and diastolic (contracture) performance. The effect is potential-dependent and not an all-or-none phenomenon; ...

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Microdialysis—Theory and application

Cited by 622 publications

References 184 publications

Extracellular Antioxidants and Amino Acids in the Cortex of the Rat: Monitoring by Microdialysis of Early Ischemic Changes

Extracellular Antioxidants and Amino Acids in the Cortex of the Rat: Monitoring by Microdialysis of Early Ischemic Changes

Stimulation of acetylcholine or dopamine receptors in the nucleus accumbens differentially alters dopamine release in the striatum of freely moving rats

Abstracts-part I (Continue in Part II)

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