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Biomedical subjects

V Pavlík

Publications and source records attributed to V Pavlík.

At least 19 recordsLinked to original sources
PubMed1999

Kainic acid increases activity only of some cortical neurons in the rat.

The influence of a subconvulsant dose of kainic acid (KA) on the activity of neurons was studied in the sensorimotor cortical area of urethane-anesthetized rats. A total of 41 neurons was recorded, 38 of these in layer V (probably pyramidal cells). The activity of 18 neurons was recorded before as well as more than 30 min after KA administration (6 mg/kg i.p.). Nine out of these 18 neurons increased their firing rate significantly even 20 min after KA injection, whereas the remaining neurons did not change their activity. Altogether, the increase in the firing rate was significant. KA was found to enhance markedly the firing rate of a part of cortical neurons at very early stages of its action.

Action Potentials↗
PubMed1994

Influence of carbamazepine and phenytoin on spontaneous activity of cerebellar neurons.

Action of carbamazepine (50 mg/kg i.p.) and phenytoin (60 mg/kg i.p.) on the activity of cerebellar neurones was studied in rats under urethane anaesthesia. Carbamazepine markedly decreased the firing frequency of all ten neurones recorded continually before and after drug administration. The same conclusion was reached when a group of 53 cells recorded before drug administration was compared with 48 neurones recorded after carbamazepine administration only. The effects of phenytoin were ambiguous--a decrease as well as an increase in frequency was recorded. The solvent used did not change cerebellar unit activity. Cerebellum cannot be considered as a possible target structure for phenytoin but it might be a target for carbamazepine action.

Animals↗
PubMed1990

[Cerebral circulation using transcranial and extracranial doppler ultrasonography in a patient with vertigo and ischemia in the area of the brain stem].

The authors examined 32 patients with vertigo, 17 patients with focal ischaemia of the brain stem and 24 patients without signs of affections of the central nervous system by transcranial and extracranial Doppler ultrasonography. They measured the flow velocity in the basilar artery (BA), in the intracranial portion of the vertebral artery (VA) and in the extracranial portion of the internal carotid artery (ICA). In patients with vertigo they investigated functional and organic changes in the area of the cervical spine. They found significant differences in the flow velocities between groups as well as in different indices calculated from the assessed values. The lowest flow velocities were recorded in patients with focal ischaemia of the brain stem. The authors evaluate the influence of haemodynamics and disease of the cervical spine on the development of vertigo.

Adult↗
PubMed1990

[Changes in circulation of the blood in cerebral arteries in relation to age].

The authors examined 12 people under 40 years and 12 above 40 years, mostly healthy volunteers. They investigated the rate of blood flow in the median cerebral artery after compression of the homolateral and contralateral internal carotid. They found that in more advanced age the rate of flow in the mentioned arteries is significantly reduced. During compression tests in more advanced age the decline in the flow rate is more marked in the median cerebral artery on the side of compression. In the other arteries the flow is promoted but the age dependence is not marked. The authors conclude from these findings that with advancing age the possibilities of autoregulation deteriorate more than those of the collateral circulation via Willis' circle.

Adult↗
PubMed1987

Ketamine blockade of cortical spreading depression in rats.

The failure to elicit cortical spreading depression (SD) under ketamine anesthesia has been examined in 25 rats. SD was elicited by microinjection of K+ acetate (1 microliter, 0.15 mol/l) into the cerebral cortex and monitored by recording the accompanying slow-potential waves. I.p. injection of ketamine HCl (50 mg/kg) elicited after 5-10 min blockade of SD propagation lasting 30-40 min. SD penetration into a cortical area superfused with 10(-4) and 10(-3) mol/l ketamine was partly or completely blocked, respectively. Systemic ketamine doses eliciting SD blockade only slightly reduced spontaneous activity of cortical units recorded with carbon fiber microelectrodes and did not increase but rather decreased the rate of K+ removal from a KCl pool (30 microliters, 40 mmol/l) contacting a 12.5 mm2 area of exposed cortical surface. The results indicate that the ketamine-induced SD blockade is due neither to epileptic activity nor to enhanced active transport of ions but rather to interference with chemically gated ionic channels and/or to stabilization of postsynaptic membranes.

Anesthesia, General↗
PubMed1987

Pseudomonas aeruginosa. II. Experimental acellular vaccine of an endotoxin and anatoxin type.

The results are given of quality evaluation of endotoxin and exotoxin antigens isolated from P. aeruginosa strains. The isolates were tested by both in vitro and in vivo methods. The results of an active protection test on white mice formed the basis for the construction of an experimental Pseudomonas vaccine that protects the immunized animals against infection even by heterologous strains of P. aeruginosa.

Animals↗
PubMed1981

Slow potential changes in experimental neocortical propagated foci.

During and following interhemispheric stimulation (HS), characteristic negative slow potential changes (NSPCs) appeared which coincided with defined patterns of epileptic phasic field potentials (PFPs). Stimulus time-locked, high-amplitude, interhemispheric responses (IHRs), interictal and ictal patterns were accompanied by typical moderate NSPCs. In the wake of the latter, giant NSPCs occurred, concurrent with Van Harrevelds convulsions and/or either total or partial spreading, or local depressions. Partial depression of the PFPs and spreading of the moderate NSPCs were also present in the IHR stage. It is suggested that the moderate and giant NSPCs characterize two distinct types of experimental epileptogenesis which differ in the extent of alteration of the extracellular ion activities.

Action Potentials↗