|
| |
|
|
The effect of antagonism of adrenergic receptors on spatial learning in laboratory rats.
Petrásek, Tomáš ; Stuchlík, Aleš (advisor) ; Otáhal, Jakub (referee)
Spatial navigation is an important aspect of animal behavior, and is often regarded as a model of higher cognitive functions, e.g. declarative memory. It can be easily assessed by various behavioral tasks ("mazes"), and compared even across different species. Therefore, spatial tasks are especially suitable for evaluating potential psychoactive drugs in an animal model. This work deals mainly with noradrenergic neurotransmitter system and its influence on learning, memory and spatial behavior. The experimental part focuses on effects of subtype-specific noradrenergic antagonists prazosin, idazoxan and propranolol, and also a D2 dopaminergic antagonist, sulpiride, in Active Allothetic Place Avoidance (AAPA) task, a novel spatial task, well suited for measuring both cognitive and motor impairments. Rats with high doses of noradrenergic antagonists show combined impairment in both cognitive and motor aspect of the task. β-adrenergic antagonist propranolol also causes specific cognitive impairment in a lower dose of 25 mg/kg, but it fails to induce long-term memory impairment when given after experimental session. Co-application of alpha-1 adrenergic and D2 dopaminergic antagonists, prazosin and sulpiride, causes a severe motor and cognitive impairment, even at doses that do not influence animal behavior when...
|
|
|
The biomechanics problems of thinwalled brain veins
Hemza, Jan ; Maršík, František (advisor) ; Otáhal, Jakub (referee) ; Vašků, Anna (referee)
Biomechanical material properties of the bridging brain veins are investigated experimentally (A Nikon light microscope was used for the histo-anatomical study and viskoelastic properties was measured on a MTS 858.2 Mini Bionix system ) and theoretically. The main goal of the developed theory was to formulate the biomechanical conditions (geometrical dimensions, viscoelastic properties of veins and blood fluid flow conditions) at which unstable behavior or even vein collapse can occur. The study of the geometry and topology of bridging veins was carried out by a magnetic resonance (Siemens Magnetom Symphony1,5 T) and a stereomicroscope (Nikon SMZ 1500) complemented with a digital camera (Nikon Coolpix E995) and Lucia Net software. From the biomechanical point of view, experimental findings can be summarized as follows: the existence of two types of venous brain systems; thin and thick wall veins with a one order difference in elastic modulus magnitude high sensitivity of the thin wall veins on the blood flow rate and extension or contraction on their structural stability the existence of continuing small wall vibration under physiological conditions Under small deformations conditions, the shear modulus was shown experimentally to be in the range (2÷4)·10 4 Pa with a Young modulus E= (0.6÷1.2)·10 5...
|
|
|
Diffusion parameters of brain tissue during ischemia and during status epilepticus
Šlais, Karel ; Syková, Eva (advisor) ; Otáhal, Jakub (referee) ; Rokyta, Richard (referee) ; Dezortová, Monika (referee)
Difusion of neuroactive substances in the extracellular space (ECS) is constrained by two factors: extracellular space volume and geometry. We have shown changes of diffusion parameters and extracellular concentrations of energetic metabolites and glutamate in two pathological states accompanied by significant ECS volume changes - in combined hypoxia/ischemia and in status epilepticus. In the model of hypoxia/ischemia, we have shown time courses of diffusion parameters, concentrations of glucose, lactate, lactate/pyruvate ratio and glutamate during hypoxic/ischemic insult and after reperfusion. The time course of glutamate extracellular concencetration in transient hypoxia/ischemia correlated well with time course of changes in diffusion parameters. The decrease in the ECS volume fraction can therefore contribute to an increased accumulation of toxic metabolites, which may aggravate functional deficits and lead to damage of the central nervous system. In the model of pilocarpine-induced status epilepticus our results show changes in the extracellular space diffusion parameters, K+, energy-related metabolites and glutamate during the initiation and first hours of the propagation. Our results also show that the first minutes after a pilocarpine injection are followed by an increase in extracellular K+ and a...
|
|
|
Anterograde tracing - a method for detection of plasticity of neuronal tracts
Krausová, Zuzana ; Otáhal, Jakub (advisor) ; Konopková, Renata (referee)
Title of work: Anterograde tracing - method for detecting conversion neuronal pathways in CNS focal lesion Objective: Create a suitable methodology for dyeing commissural fibers and its future use it to evaluate the plasticity of nerve tissue and confirmed using the anterograde tracer detecting fibers from the application site of the tracer in the contralateral projection area. Method: The experiment was carried out on adult individuals of the rat, which It was applied anterograde tracer BDA. Then we watched the ability of the tracer color commissural nerve fibers and fibers on the behavior of the application site in sensorimotor cortex. Results show that Biotinylated dextran amine is capable as anterograde tracer color neurons and fibers in the puncture cannula. However, our experiment It proves that BDA is suitable for marking commissural connections from the application site contralateral. Key words: focal cerebral ischemia, anterograde tracing, BDA, white matter, plasticity nervous tissue Powered by TCPDF (www.tcpdf.org)
|
|
|
Model of focal ischemic brain lesion in neonatal rat.
Hráchová, Anna ; Brime, Tufikameni (referee) ; Otáhal, Jakub (advisor)
Title of work: Model of focal brain ischemic lesion in neonatal rats. Work objectives: The aim of this diploma thesis was to determinate the parameter of the lesion after focal brain ischemia induced by photothrombosis, establish the changes of sensorimotor abilities and investigate the occurrence of post stroke epileptic seizures in this new model in P7 rat pups. Materials and Methods: Intravenous application of bengal rose dye was followed by illumination of concentrated beam of high powered green laser over the sensorimotocortex for 5 minutes at 0,5s on/off cycles. To assess the motor deficit, rotarod walking test and bar holding test were performed in two months after stroke. The animals underwent implantation of EEG cortical and hippocampal electrodes followed by a week of recovery four months after stroke. EEG monitoring for five consecutive days have been done. Then animals were overdosed with urethane and transcardially perfused. The brains were cut into 50μm slice for histological staining. There were another five previous experiments, which were preliminary studies aiming at correct inducing of photothrombotic stroke and also EEG monitoring at all. Every study included a control groups that underwent the same surgical protocol. Present work includes only the last sixth experiment....
|
|
|
Detection of neuronal pathways after CNS lesions by using dextran amine.
Muchová, Zuzana ; Konopková, Renata (referee) ; Otáhal, Jakub (advisor)
Title of work: Detection of neuronal pathways after CNS lesions by using dextran amine. Aim: Develop a metodology for pathway tracing with the substance transmitted by axonal anterograde transport and compare iontophoretic and pressure injection of BDA. Methods: The experiment was performed on adult rats which where injected iontophoretic and pressure anterograde tracer BDA. One week after injection were decapitated in deep anesthesia, their brains removed, frozen in dry ice and stored at -70řC. The brains were then cut into thin coronal slice (50 µm), immunolabeled and loaded on microscopic slides. Individual sections were examined labeling nerve fibers at the injection site, its surroundings and contralateral side of the hemisphere. Results: After injections of anterograde tracer BDA into the nervous tissue have been shown labeling of nerve fibers at the injection site, surroundings and contralateral side of the hemisphere. As an efficient method for its injection was determined according to results of the pressure method. Key words: anterograde tracer, BDA, iontophoretic injection, cerebral ischemia, neuroplasticity
|
|
|
Electrophysiological Models of Seizure like Activity for NO Detection in Vitro
Novák, Karel ; Konopková, Renata (referee) ; Otáhal, Jakub (advisor)
Definition of work: Electrophysiological models of seizure like activity for NO detection in vitro Supervisor: MUDr. Jakub Otáhal, PhD. Department of Anatomy and Biomechanics FTVS CUNI Department of Developmental Epileptology CAS, Institute of Physiology Consultant: Mgr. Renata Konopková Department of Developmental Epileptology CAS, Institute of Physiology Aim: The aim of the thesis is to introduce nitric oxide (NO) and its role in physiology and pathophysiolgy of central nervous system (CNS), with the intention of epileptiform activity in the nervous tissue. Our research was realized on rat hippocampal slices in vitro and it compares the experimental biochemical models (low-Mg2+ , high-K+ , Carbachol, Bicuculline and 4-Aminopyridine model). These changes in the environment of slice should evoke the epileptiform activity in the nervous tissue of the rat. The final aim of the thesis is to create an experimental model of epileptiform activity in vitro in our setup for imaging techniques and NO detection. Methods: Experiments were performed in rat hippocampal slices in vitro. Rats were deeply anaesthetized with ether and decapitated. Brain was rapidly removed from the scull, cut in oxygenated (95%) and cooled (0, 5 řC) artificial cerebrospinal fluid (ACSF) using vibratome in coronal slices of 400µm of...
|
|
|
Effect of carbon dioxide on neurovascular coupling during cortical epileptic activity in rats.
Jindrová, Martina ; Otáhal, Jakub (advisor) ; Brožíčková, Carole (referee)
Aim: The aim of the study is to investigate the effect of CO 2 on neurovascular coupling in response to epileptiform activity after trancallosal electric stimulation in rats. Methods: Adult albino rats (250-350g, n=6) were anaesthetized with isoflurane and epidural silver EEG electrodes were implanted and fixed into the skull over sensorimotor cortices. To measure regional cerebral blood flow (rCBF) during epileptic activity a self-made metal holder for Laser Doppler Flowmeter (LDF) probe was fixed to thinned skull with dental acrylic. To measure arterial blood pressure (BP) and arterial blood gasses a plastic catheter was implanted into the common carotid artery. After postsurgical recovery animals were placed in a recording chamber. After 20 minutes of background recording effect of CO 2 on basal BP an rCBF was tested by inflating a mixture of 10%CO 2 , 20%O 2 and 70%N 2 for 30seconds. To assess changes in neurovascular coupling a rat model for myoclonic seizures was used. Biphasic constant current suprathreshold stimulus (8Hz, 15s) was applied under normal or elevated CO 2 atmosphere. Results: Elevated CO2 led to a significant increase of both regional cerebral blood flow and blood pressure. In addition, inhalation of 10%CO2 during electrical stimulation of senzorimotor cortex (8Hz, 15s) caused...
|
|
|
Method for assesment of the effect of selected anesthetics on H-reflex in laboratory rat.
Komárková, Mariana ; Otáhal, Jakub (advisor) ; Konopková, Renata (referee)
Title of work: Method for Assesment of the Effect of Selected Anesthetics on H-reflex in Laboratory Rat Objective: To create an applicable method for recording of the H-reflex of freely moveable unanesthetized rats. Methods: Three adult rats were each implanted in the right leg with stimulating electrodes in a flexible cuff on the tibial nerve and a pair of recording electrodes in the triceps surae muscle. After recovering it was evaluated if the electrodes are appropriate for stimulation of peripheral nerve and for recording of ongoing EMG and evoked EMG (H-reflex, M- response). Results: It is possible to use stimulating electrodes in a flexible cuff and a pair of recording electrodes for recording ongoing EMG and evoked EMG (H-reflex, M-response) in freely moveable rats. The experiment did not determine which kind of metal is the most appropriate for conductor for recording high quality EMG. Keywords: H-reflex, Electromyography, Implanted electrodes, Rat, Electrophysiology
|
guest ::
