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C Masánová

Publications and source records attributed to C Masánová.

7 recordsLinked to original sources
PubMed1996

Transport of an antihypoxic drug stobadine across the blood-brain barrier in rat striatum and its influence on catecholamine-oxidative current: a voltammetric study under normal and anoxic/ischaemic conditions.

Differential pulse voltammetry with a carbon fibre microelectrode (ME) was used in pentobarbital-anaesthetized rats for monitoring the stobadine current (STB.C) on both sides of the blood-brain barrier (BBB) in the arterial bloodstream (BS) and in the corpus striatum (CS). The STB.C exhibited a distinct peak at a polarization voltage 540 +/- 30 mV (n = 4). The maximum of STB.C in BS attained 2-3 min after the STB administration (2.8 mg/100 g in 1.0 ml saline solution i.a.) was followed by a rapid decrease to about 20% within next 3 min. The STB readily passed across the BBB: the STB.C peak appeared in the CS in the 3rd minute and continued to rise up to the 30th min. The administration of STB did not prevent a large increase (1347 +/- 326%, n = 3) of the catechol-oxidative current (CA.OC) occurring in the CS between the 4th and 5th minute after cardiac arrest. However, a decrease of ME sensitivity to CA.OC in the presence of STB was observed. This fact leads to the speculation whether a similar "quenching" of dopamine by STB could not participate in the protective effects of STB observed in the brain exposed to hypoxia-reoxygenation.

Animals↗
PubMed1994

Decrease of extracellular catecholamine content in the vicinity of cortical penicillin-induced epileptogenic focus: voltammetric study in the rat.

Differential pulse voltammetry with carbon-fibre microelectrodes was used in chloralhydrate-anaesthetized rats to test the influence of the penicillin-G-Na (PNC)-induced (topical application, approximately 2000 IU) epileptic activity on the catecholamine content (catechol-oxidative current, CA.OC) in the parietal cortex. In the experimental group (n = 4) after PNC a nonlinear CA.OC lowering was observed; this decrease during the first 10 min was faster than in the control group (n = 4). Significantly different values were observed from the 4th min after application. The best fit for this experimental curve gave the logarithmic function (f(t) = a+b.ln(t), a = 105.8, b = -10.6) with regression coefficient r = 0.98. From the 12th min after PNC application until the end of the experiments (54th min) CA.OC values ranged from 78% to 84% of the control group.

Anesthesia↗
PubMed1994

Catecholamine overflow within rat striatum: the influence of microstimulation and electroconvulsive stimulation as observed with voltammetry.

Differential pulse voltammetry with a carbon fibre microelectrode was used in chloral hydrate-anaesthetized rats for testing the influence of microstimulation and of electroconvulsive stimulation on the changes in concentration of electro-oxidizable materials (catechol derivates) in the extracellular space of the corpus striatum. Microstimulation applied in the striatum (8 V anodal pulses, 0.1 ms, 100 Hz for 40 s) caused a significant increase of the catechol-oxidative current (Ico); 5 s after microstimulation was stopped Ico ranged from 117 to 141% of the control (all values means +/- S.D. unless otherwise stated; 124 +/- 11%, n = 4, P < or = 0.01, Student's t test). This effect ceased in the third minute after microstimulation. A comparable result was observed when microstimulation was repeated at intervals of 10 min. Electroconvulsive stimulation with a sinusoidal current (50 Hz, approximately 150 mA, 0.2 s) caused a large increase in Ico; 20 s after stimulation ceased, Ico was 987 +/- 90% (n = 3) of the control and it returned to the baseline 2 min later. The mechanisms inducing transmitter overflow are considered and the influence of electroconvulsive stimulation on the striatum is discussed in the context of its beneficial effects in psychopathic patients.

Animals↗
PubMed1994

Effects of electroconvulsive shock on catecholamine release in the corpus striatum of the rat: a voltammetric study.

A voltammetric technique was used (differential pulse voltammetry with a carbon fibre microelectrode) to investigate dynamics of the changes of catecholamine overflow in the corpus striatum following electroconvulsive stimulation (ECS) of chloral hydrate-anaesthetized rats. Application of "maximal" ECS (50 Hz, AC, sine wave, approximately 150 mA, 0.2 s) caused large enhancement of catechol-oxidative current (CA.OC): In the first minute after its arrest, the CA.OC peak raised to 1032 +/- 405% (n = 5, mean +/- S.D.) of the controls (P < or = 0.001, Student's t-test). This large elevation of the extracellular catecholamine content ceased rapidly--the baseline level was attained in the second minute. CA.OC changes evoked by a "minimal" ECS (50 Hz, AC, sine wave, approximately 30 mA, 0.2 s) were equivocal in the first minute (increase, decrease: 145 +/- 56%, P > 0.05, n = 6). Possible mechanisms of the ECS therapeutic effect are discussed.

Animals↗
PubMed1993

Increase of catecholamine content in the extracellular space of the rat's brain cortex during spreading depression wave as determined by voltammetry.

The effect of chemically initiated (KCl) spreading cortical depression on catecholamine content in the extracellular cortical space was examined using voltammetry technique in chloralhydrate-anaesthetized rats. Correlation between alterations in catechol-oxidative current (CA.OC) and the time-course of the slow potential (SP) change (one of the chief features of the spreading depression) showed that spreading depression wave was accompanied by the significant increase in CA.OC content (up to 158 +/- 43%, mean +/- S.D., P < 0.001). The rise of the negative SP preceded significant CA.OC increase by 20 +/- 8 s. This fact provides the evidence that catecholamine overflow cannot participate in triggering spreading depression wave; nevertheless it can be an important link of the spreading depression mechanism.

Animals↗
PubMed1992

Voltammetrically determined differences in changes evoked by KCl microinjections on catecholamine levels in the reticular formation and corpus striatum of the rat.

Using a microelectrode with carbon filaments and the voltammetric technique, changes evoked in the catechol oxidation current (CA.OC) and multiple unit activity (MUA) by microinjection of 3-5 microliters 0.5 mol.l-1 KCl were studied in the reticular formation (RF) of the medulla oblongata of anaesthetized rats; the effect of KCl stimulation of the RF and corpus striatum (S) on the CA.OC in these structures was compared. The microinjection of KCl in the vicinity of the working electrode in the RF caused depression of MUA which began 2-3 s after administration, persisted for up to 6 min after and then diminished, reaching control values within 9 min. The voltammetric signal was first recorded in the 1st min after microinjection, when there was an evident decrease in the CA.OC value (59% of the control value); this effect reached its maximum 7 min after administration (a mean drop to 23% of the control), while at the end of the experiment (i.e. after 24 min) CA.OC values had risen to 45-80% of the control value. The response in the S had a biphasic character, however. Immediately after the microinjection (1st min), the mean CA.OC value rose to 626% of the control, while in the second phase (3-10 min) it was seen to fall below the control values (means 21-63% of the control). The differences in the changes evoked by K+ depolarization in the concentration of catecholamines in the RF and S microenvironment are discussed from the aspect of the existence of different pools of the transmitter and other regional differences.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗