Preferencje help
Polish version English version Język
Widoczny [Schowaj] Abstrakt
Liczba wyników

Znaleziono wyników: 14

Liczba wyników na stronie
Pierwsza strona wyników Pięć stron wyników wstecz Poprzednia strona wyników Strona / 1 Następna strona wyników Pięć stron wyników wprzód Ostatnia strona wyników

Wyniki wyszukiwania

help Sortuj według:

help Ogranicz wyniki do:
Pierwsza strona wyników Pięć stron wyników wstecz Poprzednia strona wyników Strona / 1 Następna strona wyników Pięć stron wyników wprzód Ostatnia strona wyników
1

Changes in electrophysiological properties of motoneurones innervating rat medial gastrocnemius in response to the muscle overload

100%
Haluszka A., Baczyk M., Celichowski J., Krutki P.
Acta Neurobiologiae Experimentalis
|
2011
|
tom 71
|
nr S
Various models of chronic muscular activity, as workload training, tendon transfer, or paresis and peripheral nerve damage are examples leading to muscle overload, which may induce measurable effects in motor units. The aim of this study was to investigate whether 5-week overloading of muscles connected with their voluntary activation in a running wheel and by a treadmill training change electrophysiological properties of their motoneurons. Rats were subjected to chronic overload of the medial gastrocnemius (MG) muscle by cutting the lateral gastrocnemius, soleus and plantaris muscles from the Achilles tendon and sewing them directed proximally to the skin. As the result of this operation, only the MG muscle was able to evoke a foot plantar flexion during the daily locomotor activity. After one week of convalescence, rats were subjected to extensive voluntary activity on a running wheel and additionally to a training program on a treadmill (1 hour daily with a speed of 27 cm/s) for 5 weeks, 5 days a week. The acute experiments were carried out on the MG motoneurones in deeply anaesthetized animals. Intracellular recordings were performed from MG motoneurones located in L4-L5 spinal segments using glass micropipettes filled with 2 M potassium citrate solution. The results were compared to the control group of normally active, intact animals. Parameters of antidromic action potentials were measured and effects of intracellular injection of rectangular pulses of depolarization current were analyzed. The basic electrophysiological properties were considerably modified by the overloading either in fast and slow motoneurones. Moreover, we observed changes in their rhythmic properties, as the increased maximum steady-state frequencies of motoneuronal firing resulting in changes in the course of the steady-state frequency-current curves in the overloaded animals. The results of this study may help understand neuromuscular mechanisms of plasticity of overloaded muscles.
2

Long-lasting effects of trans-spinal direct current stimulation on motoneuron firing properties in rats

100%
Krutki P., Drzymala-Celichowska H., Mrowczynski W., Baczyk M.
Acta Neurobiologiae Experimentalis
|
2019
|
tom 79
|
nr Suppl.1
INTRODUCTION: Trans-spinal direct current stimulation (tsDCS) is a neuromodulative technique used to improve motor functions in neurological disorders and to facilitate sport performance. However, despite the broad application of spinal cord polarization, the physiological mechanisms behind the observed effects remain unclear. We have recently demonstrated that anodal or cathodal tsDCS can alter motoneuron membrane properties and firing characteristics during its application and beyond. AIM(S): The aim of this study was to determine whether these alterations persist over a longer period of time. METHOD(S): The study was performed on adult male Wistar rats under general anesthesia. Anodal or cathodal tsDCS (0.1 mA, 15 min) was applied through an electrode located on the lumbar vertebra above the recording site. The intracellular recordings from L4‑L5 spinal motoneurons were performed at various periods after the offset of polarization (up to 3 hours). The animals not subjected to tsDCS formed the control group. RESULTS: Anodal tsDCS evoked a significant decrease in the voltage threshold, the rheobase, the threshold for rhythmic steady-state firing, as well as, an increase in the steady‑state firing frequencies and the slope of the frequency‑current relationship. Some of these modulatory effects were observed up to 60 minutes after the offset of polarization. Cathodal tsDCS induced only modest changes in motoneuron threshold properties, which could be observed no longer than 30 minutes after the end of polarization. CONCLUSIONS: This study for the first time provides the direct evidence that tsDCS evokes long-term alterations in the threshold and rhythmic firing properties of spinal motoneurons. Modulatory effects of anodal polarization are stronger and last longer than those of cathodal tsDCS. We suppose that both autonomous cell mechanisms and synaptic effects contribute to the occurrence and long-term persistence of the indicated changes in motoneuron properties. FINANCIAL SUPPORT: Supported by the National Science Center grant No 2017/25/B/NZ7/00373.
3

Modification of monosynaptic Ia EPSP by externally induced electrical fields in SOD1 G93A mouse model of amyotrophic lateral sclerosis

100%
Baczyk M., Jankowiak T., Cholewinski M.
Acta Neurobiologiae Experimentalis
|
2019
|
tom 79
|
nr Suppl.1
Amyotrophic lateral sclerosis (ALS) is a fatal neurodegenerative disease characterized by a progressive loss of motoneurons with no viable treatment available. A dysregulation of facilitation/inhibition coupling that forces motoneuron hypoexciatability appears to be a key mechanism of the degeneration, and preliminary results suggest that the chemogenetic increase of motoneuron activation ameliorates the disease burden. AIM(S): Here we propose a novel method of manipulating motoneuron synaptic excitation in the SOD1 mouse model of ALS, using the trans-spinal direct current stimulation (tsDCS) technique, which influences both motoneuron intrinsic excitability and synaptic excitation. METHOD(S): Experiments were carried out on presymptomatic SOD1‑G93A mice. Animals were deeply anesthetized with a mix of fentanyl/medetomidine/ midazolam, artificially ventilated, and paralyzed. Intracellular recordings of triceps surae (TS) motoneurons allowed recording of monosynaptic EPSPs from electrically stimulated proprioceptive Ia afferents, which were subsequently conditioned with cathodal tsDCS of 0.1 mA. RESULTS: Cathodal polarization evoked an acute increase of the Ia EPSP amplitude recorded in TS motoneurons (max 200% of control n=10). These alterations were not matched by changes in the Ia afferent activity or motoneuron passive membrane properties, suggesting that the loci of the effects is restricted to the pre- or postsynaptic elements of the Ia synapse. Interestingly, the effects of polarization outlasted its application by at least 15 min. CONCLUSIONS: tsDCS is a potent way of manipulating motoneuron synaptic excitation and may play a role as a therapeutic method for managing ALS. However, the influence of this technique on motoneuron intrinsic excitability and disease progression remains to be elucidated. FINANCIAL SUPPORT: This work was supported by NCN grant no. 2017/26/D/NZ7/00728.
4

Stochastyczna ocena sieci monitoringu

100%
Straszko J., Baczyk M., Mozejko J.
Ochrona Powietrza i Problemy Odpadów
|
1998
|
tom 32
|
nr 2
39-47
5

Changes in the force-frequency relationship after the treadmill and whole body vibration training of motor units in rat medical gastrocnemius muscle

100%
Baczyk M., Lochynski O., Celichowski J.
Acta Neurobiologiae Experimentalis
|
2009
|
tom 69
|
nr 3
The aim of the study was to compare changes in the force-frequency relationship of motor units (MUs) in rat medial gastrocnemius muscle, caused by treadmill training and whole body vibration training. 24 Wistar rats were studied. Rats were divided into 3 groups: treadmill training group (n=7, locomotion speed 27 cm/s, 1 km daily, 5 days weekly, for 4 weeks), whole body vibration training group (n=6, Power Plate® vibration platform, 50 Hz vibration of 2 mm amplitude, 30 s daily, 5 days weekly, for 4 weeks) and a control group n=11. Functional isolation of single MUs was achieved by electrical stimulation of ventral roots fi laments. A total of 424 MUs were studied (148 in treadmill training, 142 in vibration training and 134 in control). MUs were classifi ed as fast fatigable – FF, fast resistant – FR or S – slow. The frequency causing 60% of maximum force of MUs has decreased in FF units of both trained groups and increased in FR units. In S units the increase of the parameter was noted only in treadmill trained group. Additionally, the slope of the force-frequency curve has increased in all MUs types in the vibration training group.
6

Subcortical effects of transcranial direct current stimulation (tDCS)

100%
Baczyk M., Bolzoni F., Jankowska E.
Acta Neurobiologiae Experimentalis
|
2013
|
tom 73
|
nr Suppl.1
Subcortical effects of tDSC were tested on direct and transsynaptic (monosynaptic) activation of reticulospinal and rubrospinal neurons in anesthetised rat and cat preparations. Rubrospinal neurons were activated by stimuli applied in the red nucleus (RN) and reticulospinal neurons via collaterals of reticulospinal neurons stimulated in the medial longitudinal fascicle (MLF), or collaterals of corticospinal neurons stimulated in the ipsilateral pyramidal tract (iPT). Responses of these neurons were facilitated by anodal polarization of the brain in the cat and by cathodal polarization in the rat. Facilitation was expressed by an increase in the amplitude and a decreased in the latency of EMG responses in the rat and of the descending volleys in the cat. tDCS did not facilitate actions of iPT neurons alone, but it increased the probability of activation of reticulospinal neurones by joint actions of ipsilateral and contralateral PTs, especially together with the MLF. All the facilitatory effects of tDCS outlasted its application up to 2 hours.
7

Intracellular recording of mouse spinal motoneurons in vivo

100%
Jankowiak T., Cholewinski M., Baczyk M.
Acta Neurobiologiae Experimentalis
|
2019
|
tom 79
|
nr Suppl.1
INTRODUCTION: Spinal motoneurons represent the final common pathway of the motor system. They are not static elements of the network, but alterations in the levels of physical activity or pathological mechanisms are known to affect their electrophysiological properties. Sharp intracellular recordings are the firmly established gold standard for studying motoneuron excitation/inhibition patterns in vivo in adult animals; however, until recently this technique was not available for mice. We’ve set out to create an electrophysiological setup that would allow us to perform stable intracellular recordings of mouse motoneurons in vivo in order to take advantage of numerous genetic models available for this organism. METHOD(S): Animals were anesthetized with a mix of fentanyl/medetomidine/midazolam, and a complex surgical procedure was performed, that included catheterization of the jugular vein, insertion of a tracheal tube, exposure of the triceps surae (TS) nerve, and Th13‑L2 laminectomy. Sharp glass microelectrodes were inserted into the spinal cord using motorized micromanipulator, and TS nerve was stimulated with constant current pulses in order to evoke motoneuron antidromic activation. Upon successful penetration, TS motoneurons were identified based on an “all or nothing” appearance of action potential, and passive, threshold and synaptic properties were recorded using intracellular stimulation/amplifier. At the end of the experiment, mice were euthanized with overdose of barbiturates. RESULTS: Our approach enabled us to record 2-5 motoneurons in a single experiment with stability ensuring precise measurement of passive membrane properties, intrinsic excitability, and synaptic excitation. CONCLUSIONS: We prove the feasibility of performing stable intracellular recordings of mouse spinal motoneurons in vivo, which should pave the way for future studies of motoneuron plasticity under physiological or pathological conditions. FINANCIAL SUPPORT: This work was supported by NCN grant no. 2017/26/D/NZ7/00728.
8

Properties of rhythmic firing of motoneurons are altered in response to weight-lifting training in rats

88%
Krutki P., Mrowczynski W., Baczyk M., Lochynski D., Celichowski J.
Acta Neurobiologiae Experimentalis
|
2017
|
tom 77
|
nr Suppl.1
INTRODUCTION: Repeated short-term and high--intensity exercises with a progressive external load are defined as strength or resistance training, which is responsible for an increase in muscle mass and force. AIM(S): The aim of this study was to determine whether strength training induces adaptive changes in firing properties of motoneurons (MNs) innervating the trained muscles. METHOD(S): The study was performed on adult male Wistar rats. Animals from the training group were subjected to a five‑week voluntary progressive weight‑lifting program, while control rats were restricted to standard cage activity. Intracellular recordings from lumbar spinal MNs innervating gastrocnemius and soleus muscles were made under pentobarbital anesthesia. RESULTS: The strength training evoked adaptive changes in both slow and fast-type MNs, indicating their increased excitability: a higher input resistance, a lower rheobase, a decrease in the minimum currents required to evoke rhythmic firing. The maximum frequencies of the early‑state firing (ESF) and of the steady‑state firing (SSF) were increased. Moreover, higher ESF and SSF slopes of the frequency-current relationship were observed in MNs of the trained group. Higher maximum firing rates of MNs as well as higher discharge frequencies evoked at the same level of intracellular depolarization current imply higher levels of tetanic forces developed by motor units over the operating range of force production after the strength training. CONCLUSIONS: This study provides evidence that the changes in spinal excitability following strength training observed in humans may be due to changes in the intrinsic properties of the MNs. The findings largely explain why some adaptations in the twitch and tetanus force development of motor units could be observed in response to the dynamic resistance training without qualitative changes in the muscle myosin heavy-chain expression. FINANCIAL SUPPORT: The study was supported by the National Science Center grant 2013/11/B/NZ7/01518.
9

Changes in electrophysiological properties of rat hindlimb spinal motoneurons evoked by the whole body vibration

88%
Mrowczynski W., Baczyk M., Haluszka A., Celichowski J., Krutki P.
Acta Neurobiologiae Experimentalis
|
2013
|
tom 73
|
nr Suppl.1
The whole body vibration training was performed on adult male Wistar rats. The experimental group subjected to a whole body vibration consisted of seven rats, while the control group of nine rats. The training program included 5 weeks and was applied by 5 days a week. Each daily session consisted of four 30-s runs of vibration at 50 Hz. Intracellular properties of motoneurones were investigated during experiments on deeply anesthetized animals. It was demonstrated that a whole body vibration evoked adaptations in excitability and firing properties of fast-type motoneurons, exclusively. A significant decrease in rheobase current and a decrease in the minimum and the maximum currents required to evoke steady-state firing in motoneurons were revealed. These changes resulted in a leftward shift of the frequency-current relationship, combined with an increase in slope of this curve. These results showed that fast motoneurons of rats after vibration have the ability to produce series of action potentials at higher frequencies in a response to the same intensity of activation. Obtained data provided direct evidence on motoneuronal plasticity following a whole body vibration.
10

Automatyzacja spektrofotometrycznej metody oznaczania jodu w moczu przy użyciu analizatora biochemicznego COBAS-BIO

88%
Knitter B., Baczyk M., Lisiecka M., Bednarek J., Gembicki M.
Diagnostyka Laboratoryjna i Wiadomości PTDL
|
1993
|
tom 29
|
nr 2
11

IA monosynaptic pathway in SODI mouse model of amyothropic lateral sclerosis

88%
Baczyk M., Martinot C., Delestree N., Manuel M., Zytnicki D.
Acta Neurobiologiae Experimentalis
|
2015
|
tom 75
|
nr Supl.
BACKGROUND AND AIMS: Glutamate excitotoxicity has long been suggested to contribute to the degeneration of motoneurons in Amyotrophic Lateral Sclerosis (ALS). However, it has recently been shown that spinal motoneurons do not display an intrinsic hyperexcitability just prior to their degeneration in SOD1 G93A mice, the standard model of ALS. Furthermore average densities of excitatory (VGLUT1 and VGLUT2) and inhibitory (VGAT) boutons on the dendritic tree and the soma of affected motoneurons were unchanged. However glutamate excitotoxicity can still take place if excitatory pathways are more active. Therefore the aim of this study was to investigate the excitability of the monosynaptic Ia pathway in SOD1 mice. METHODS: Eight SOD1 G93A and six SOD WT control mice were used in this study. Intracellularly penetrated motoneurons were identified as a medial gastrocnemius (MG) or lateral gastrocnemius (LG) motoneurons by their threshold for antidromic activation. Ia monosynaptic EPSPs were recorded from these motoneurons after stimulation of their homonymous nerve. In parallel the afferent Ia volley was recorded from the cord dorsum. Increasing stimulation intensities were used to obtain minimum and maximum Ia Volleys and EPSPs. RESULTS: The average amplitudes of monosynaptic Ia EPSPs in SOD1 motoneurons were significantly smaller when compared to SOD WT controls (1.40 mV and 2.24 mV, respectively). Moreover the EPSP difference was mainly visible for the group of motoneurons characterized by high input resistance (above 3 MΩ). On the other hand, the recruitment curves (normalized amplitude vs. stim intensity) of Ia volleys and EPSPs were unchanged, suggesting no change in excitability of Ia fibers but alterations in Ia monosynaptic synapses. CONCLUSIONS: Results indicate alterations in Ia monosynaptic pathway in presymptomatic SOD1 ALS mouse model. This can stem from several reasons, e.g. increased presynaptic inhibition of Ia terminals or reduced efficacy of post-synaptic receptors.
12

Peptide receptor radionuclide therapy of differentiated thyroid cancer: efficacy and toxicity

76%
Czepczynski R., Matysiak-Grzes M., Gryczynska M., Baczyk M., Wyszomirska A., Stajgis M., Ruchala M.
Archivum Immunologiae et Therapiae Experimentalis
|
2015
|
tom 63
|
nr 2
13

Changes in electrophysiological properties of rat motoneurons evoked by A5-week sterngth training

76%
Mrowczynski W., Lochynski D., Kaczmarek D., Baczyk M., Celichowski J., Krutki P.
Acta Neurobiologiae Experimentalis
|
2015
|
tom 75
|
nr Supl.
BACKGROUND AND AIMS: Different forms of chronic physical activity evoke adaptive changes in the neuromuscular system. Long-lasting strength training, with repeated short-term and highintensity exercises, is responsible for an increase of muscle mass and generation of larger forces. However, adaptations in properties of motoneurons innervating muscles subjected to such training have been unknown so far. The aim of this study in the rat was to determine whether the strength training induces changes of passive and threshold membrane properties, and rhythmic firing of motoneurons. METHODS: The study was performed on eight adult Wistar rats, randomly assigned to the training or the control groups. Animals from the training group were nutritionally conditioned in order to make weightlifting put on their shoulders in a special apparatus with progressively increasing load, for 5 weeks. Acute electrophysiological experiments were performed on deeply anesthetized animals from both groups, using microelectrode intracellular recordings from motoneurons innervating hind limb muscles. RESULTS: It was demonstrated that 5-week strength training evoked adaptive changes in both fast and slow types of motoneurons: a shortening of the rise time of action potentials, an increase of the maximum frequencies of rhythmic firing, and an increase in the slope of the frequency-current relationship. CONCLUSIONS: Obtained data suggest higher susceptibility of motoneurons to an increased or decreased intensity of stimulation. Moreover, a decrease in rheobase currents, and a decrease in the minimum currents required to evoke rhythmic firing was observed in fast-type motoneurons only, suggesting their higher excitability. Supported by the National Science Center grant No. 2013/11/B/ NZ7/01518.
14

The role of serum C-reactive protein measured by high-sensitive method in thyroid disease

52%
Czarnywojtek A., Owecki M., Zgorzalewicz-Stachowiak M., Wolinski K., Szczepanek-Parulska E., Budny B., Florek E., Waligorska-Stachura J., Miechowicz I., Baczyk M., Sawicka N., Dhir S., Ruchala M.
Archivum Immunologiae et Therapiae Experimentalis
|
2014
|
tom 62
|
nr 6
Pierwsza strona wyników Pięć stron wyników wstecz Poprzednia strona wyników Strona / 1 Następna strona wyników Pięć stron wyników wprzód Ostatnia strona wyników
JavaScript jest wyłączony w Twojej przeglądarce internetowej. Włącz go, a następnie odśwież stronę, aby móc w pełni z niej korzystać.