Search results for "Extracellular fluid"
showing 10 items of 27 documents
Effects of Anandamide and Noxious Heat on Intracellular Calcium Concentration in Nociceptive DRG Neurons of Rats
2007
As an endogenous agonist at the cannabinoid receptor CB1 and the capsaicin-receptor TRPV1, anandamide may exert both anti- and pronociceptive actions. Therefore we studied the effects of anandamide and other activators of both receptors on changes in free cytosolic calcium ([Ca2+]i) in acutely dissociated small dorsal root ganglion neurons (diameter: ≤30 μm). Anandamide (10 μM) increased [Ca2+]iin 76% of the neurons. The EC50was 7.41 μM, the Hill slope was 2.15 ± 0.43 (mean ± SE). This increase was blocked by the competitive TRPV1-antagonist capsazepine (10 μM) and in Ca2+-free extracellular solution. Neither exclusion of voltage-gated sodium channels nor additional blockade of voltage-gate…
Tumour tissue monitoring during photodynamic and hyperthermic treatment using bioimpedance spectroscopy.
2003
Electrical bioimpedance spectroscopy is a fast and relatively easily applicable method for tissue characterization. In the frequency range up to 10 MHz, current conduction through tissue is mainly determined by tissue structure, i.e. the extra- and intra-cellular compartments and the insulating cell membranes. Therefore, changes in the extra- and intra-cellular fluid volumes are reflected in the impedance spectra. Investigations of tumours (DS sarcoma, implanted on the hind foot dorsum of rats) during treatment with localized hyperthermia (HT), photodynamic therapy (PDT) and the combination of these two components were carried out using impedance spectroscopy in the frequency range of 37 Hz…
Plasma Insulin Levels and Hypoglycemia Affect Subcutaneous Interstitial Glucose Concentration
2018
[EN] Background: Continuous glucose monitoring (CGM) accuracy during hypoglycemia is suboptimal. This might be partly explained by insulin or hypoglycemia-induced changes in the plasma interstitial subcutaneous (SC) fluid glucose gradient. The aim of the present study was to assess the role of plasma insulin (PI) and hypoglycemia itself in the plasma and interstitial SC fluid glucose concentration in patients with type 1 diabetes mellitus. Methods: Eleven subjects with type 1 diabetes (age 36.59.1 years, HbA(1c) 7.90.4% [62.8 +/- 2.02mmol/mol]; mean +/- standard deviation) were evaluated under hyperinsulinemic euglycemia and hypoglycemia. Each subject underwent two randomized crossover clam…
Selective activation of 5-HT(2C) receptors stimulates GABA-ergic function in the rat substantia nigra pars reticulata: a combined in vivo electrophys…
2007
In vivo electrophysiology and microdialysis were used to investigate the physiological role of 5-HT(2C) receptors in the control of substantia nigra pars reticulata (SNr) function. Extracellular single-unit recordings were performed from putative GABA-containing neurons in the SNr of anesthetized rats, and local GABA release was studied by in vivo microdialysis in the SNr of awake freely-moving rats. Systemic administration of the selective 5-HT(2C) receptor agonist (S)-2-(chloro-5-fluoro-indol-1-yl)-1-methylethylamine 1:1 C(4)H(4)O(4) (RO 60-0175) caused a dose-dependent excitation of about 30% of the SNr neurons recorded. However, the remaining neurons were either inhibited or unaffected …
Local salsolinol modulates dopamine extracellular levels from rat nucleus accumbens: shell/core differences.
2008
Salsolinol (SAL), a condensation product of dopamine and acetaldehyde that appears in the rat and human brain after ethanol ingestion, has been largely implicated in the aetiology of alcoholism. Although the behavioural consequences of systemic or intracerebral SAL administrations have been described, the neurochemical effects of pharmacologically relevant doses of SAL and other tetrahydroisoquinolines (THIQs) in the brain areas involved in alcohol addiction are practically unknown. To gain an insight into this topic, male Wistar rats were stereotaxically implanted with one concentric microdialysis probe in either the shell or the core of the nucleus accumbens (NAc). Treatments involved loc…
Detection of flap venous and arterial occlusion using interstitial glucose monitoring in a rodent model.
2010
Background: Free tissue transfer necessitates vigilant postoperative monitoring for vessel occlusion. Unfortunately, most monitoring methods require experienced personnel and are expensive to use. Furthermore, many tests have low sensitivity, low specificity, or significant delay between vessel occlusion and detection. The authors report on a novel method of tissue monitoring that avoids these limitations by tracking interstitial glucose concentration. Methods: Vertical rectus abdominis myocutaneous flaps were elevated in adult rats based on the superior epigastric vessels. Interstitial glucose within the flaps was monitored using a transcutaneous sensor. Interstitial glucose was recorded f…
KA-672 inhibits rat brain acetylcholinesterase in vitro but not in vivo.
1999
Abstract KA-672, a lipophilic benzopyranone derivative which is currently under development as a cognitive enhancer and antidementia drug, has previously been shown to have facilitatory effects on learning and memory in rats at doses of 0.1–1 mg/kg. We now report that KA-672 inhibited the activity of acetylcholinesterase (AChE), measured in vitro in rat brain cortical homogenate, with an IC 50 value of 0.36 μ M indicating that KA-672 may improve cognitive functions as a consequence of AChE inhibition. However, when we employed the microdialysis procedure to monitor acetylcholine (ACh) release from rat hippocampus, no effect of KA-672 (0.1–10 mg/kg) was found, indicating a lack of inhibition…
Inhibition of the myosin light chain kinase prevents hypoxia-induced blood-brain barrier disruption
2007
Increased mortality after stroke is associated with development of brain edema. The aim of the present study was to examine the contribution of endothelial myosin light chain (MLC) phosphorylation to hypoxia-induced blood-brain barrier (BBB) opening. Measurements of trans-endothelial electrical resistance (TEER) were performed to analyse BBB integrity in an in vitro co-culture model (bovine brain microvascular endothelial cells (BEC) and rat astrocytes). Brain fluid content was analysed in rats after stroke induction using a two-vein occlusion model. Dihydroethidium was used to monitor intracellular generation of reactive oxygen species (ROS) in BEC. MLC phosphorylation was detected using i…
Anoxia in vitro does not induce neuronal swelling or death
1996
To improve the understanding of neuronal cell swelling in cerebral ischemia, cell volume regulation, viability, intracellular electrolytes, and lactate production of Neuro-2A neuroblastoma cells were studied using an in vitro model. The volume regulatory capacity of Neuro-2A cells was assessed after incubation in hypo- and hypertonic media. Anoxia was studied alone and together with inhibition of glycolysis by iodoacetate. Reducing the tonicity of the incubation medium to 250, 200, or 150 mosm/l caused immediate swelling followed by a regulatory volume decrease within 20 min, which, however, was not complete. The final cell volume after regulation depended on the tonicity of the medium and …
Extracellular space and electrolyte distribution in cortex and white matter of dog brain in cold induced oedema
1973
24 hours after a circumscribed cold injury of the cortex dog brains were perfused from the lateral ventricle and the frontal subarachnoidal space to the cisterna magna with an artificial CSF containing trace amounts of35S-labelled thiosulphate. Simultaneously the extracellular tracer was administered intravenously. Extracellular fluid volume was estimated and found to be increased from 10 to 15% in the oedematous cortex and from 10 to 27% in the oedematous white matter. The actual size of ECS in oedematous white matter, however, must be larger as indicated by the relative alterations of thiosulphate distribution, tissue water, sodium and chloride. Apparently a small part of the fluid accumu…