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EN
The image of Adam Mickiewicz that emerges from the very few remarks in the writings of Gérard de Nerval is interesting, though incomplete, since it is based only on certain ideas expressed in Mickiewicz's lectures at the College de France and in his 'Ksiegi narodu polskiego i pielgrzymstwa polskiego' (Books of the Polish Nation and of the Polish Pilgrimage). The French romantic poet equated Mickiewicz with the many representatives of syncretic religious movements popular in nineteenth-century France. In his letters and articles, Nerval interpreted the Polish poet's words as he sought in them a solution to his own faith dilemmas. Nerval's statements on the subject of Mickiewicz are confronted with the two final courses of the Paris lectures, where Mickiewicz deals with the issues that most interested Nerval: metempsychosis, modern pantheism, the relationship of the followers of religious eclecticism to the official Church, the mission of the Slavs, the role of Napoleon. A comparative reading enables us to shed closer light on little known aspects of Mickiewicz's work, as well as to comprehend certain tendencies in the writings of the French romantic poet.
EN
This article discusses the evolution of Adam Mickiewicz's lyrical-text subject through the prism of the motif of navigation in the poet's oeuvre. Pieces of verse written in various phases of his artistic activity have been analysed: from classicist juvenile poems (Juz sie z pogodnych niebios ...), programmatically Romanticist poems (two poems titled Zeglarz (The Sailor), pieces written down in period 'memory albums', the 'maritime' cycle of 'Sonety krymskie' (The Crimean Sonnets), 'Do samotnosci', through to late verse, religious and thoughtful as it was ('Rozum i wiara', 'Widzenie', and, especially, the 'Lausanne Lyrics' cycle). In the earliest poems, the image of moving across the water expresses shared strivings of a collective subject; in the romanticist pieces, it turns out to be a lone action taken by a 'strong self' being aware of its unique quality and not understood by the others. In the later poems, where a personal aspect tends to disappear, sailing turns into the former 'self' flowing across or even disappearing. In Mickiewicz's lyrics, the transformation of the sailing motif occurs as the poet's gradually freeing himself from the metaphor in question and from identifying the subjectivity of his poems with the figure of a sailor.
PL
W artykule przedstawiono dyskretny model typu ARMA technologicznego procesu flotacji rudy cynkowo-ołowiowej. Obiektem badań był węzeł wzbogacania flotacyjnego tej rudy w WPM "Olkusz-Pomorzany" ZGH "Bolesław". Mierzonymi parametrami procesu, które wykorzystano w modelu, były zawartości składników użytecznych i towarzyszących w nadawie oraz w otrzymywanych produktach. Dane pomiarowe pochodziły z zainstalowanego w Zakładzie systemu sond rentgenofluorescencyjnych.
EN
Discrete ARMA type model for technological floatation process of Zn-Pb ore was described. The floatation enrichment of the ore at WPM "Olkusz-Pomorzany" at ZGH "Bolesław" was studied. Contents of useful and accompanying components in fed material as well as in obtained products were determined and then used in modelling. Data were measured by a system of x-ray fluorescent probes installed in the plant.
EN
INTRODUCTION: Experimental evidence points to the 5-HT7 receptor as a potential therapeutic target for affective and neurodevelopmental disorders. The cellular/ ionic mechanisms following the activation of the 5-HT7 receptor signaling pathway have not yet been fully characterized. Our preliminary recordings from hippocampal neurons have shown that 5-HT7 activation, in addition to increasing neural excitability, shortens action potential latency, which suggests involvement of voltage-gated potassium channels in the neural response to 5-HT7 activation. AIM(S): The aim of our study was to directly investigate modulatory effects of 5‑HT7 activation on voltage‑gated potassium channels in rat CA1 pyramidal cells, as well as to examine the functional consequences of such effects on the hippocampal circuitry. METHOD(S): We performed whole-cell voltage clamp recordings from rat CA1 pyramidal cells and tested the effects of 5‑HT7 agonists on A‑type and delayed rectifier potassium currents. To examine the influence of the 5-HT7-mediated channel modulation on synaptic transmission, we stimulated Schaffer collaterals and recorded evoked AMPA currents before and after 5-HT7 activation, as well as before and after blocking Kv4.3/Kv4.4 and/or HCN channel subunits. RESULTS: Activation of 5-HT7 receptors markedly attenuated A-type potassium currents in CA1 pyramidal cells. Furthermore, 5-HT7 activation increased AMPA postsynaptic currents evoked by stimulation of Schaffer collaterals, and this effect was partially dependent on the inhibition of A-type potassium channels. CONCLUSIONS: We found that 5-HT7 receptors can strongly influence neural activity by inhibiting A‑type potassium currents, which affects both neural excitability and response dynamics, as well as CA3 -> CA1 synaptic transmission. FINANCIAL SUPPORT: The study was supported by Ministry of Science and Higher Education (Warsaw, Poland) grant no 2016/21/B/NZ4/03618 and statutory funds from the Institute of Pharmacology Polish Academy of Sciences, Krakow, Poland. M.S. and J.E.S. are beneficiaries of the KNOW PhD scholarship sponsored by the Ministry of Science and Higher Education, Poland.
EN
The nucleus incertus (NI) is a group of GABAergic neurons located in the midline tegmentum. It is the main source of the neuropeptide relaxin-3, which has been shown to be involved in appetite control, modulation of arousal and stress responses, as well as hippocampal theta rhythm. This is similar to the profile of orexins – neuropeptides expressed in the lateral and perifornical hypothalamus. Orexin neurons innervate numerous brain areas, including the brainstem, and activate g-protein-coupled receptors OXR1 and OXR2. This can lead to cell membrane depolarization through a number of possible mechanisms, including increases in intracellular calcium levels. We performed whole-cell patch clamp recordings from NI neurons in rat brain slices. To examine mechanisms of orexin receptor activation, recordings were made using TTX and calcium channel blockers: nickel chloride and nifedipine. We found the depolarizing effect of orexin A on NI neurons was reduced in the presence of calcium channel blockers. These findings help better understand the nature of interactions between the two peptide systems. Combined with further research, they could shed light on the possible involvement of the NI relaxin-3 system in the interplay between arousal, feeding and spatial memory.
EN
INTRODUCTION: Emerging evidence suggests the 5-HT7 receptor as a therapeutic target in stress-related disorders. Precise effects of the 5‑HT7‑mediated regulation of neuronal excitability remain to be elucidated. Preliminary recordings from rat CA1 piramidal neurons showed that 5-HT7 activation shortens the latency of the first spike in response to depolarization. Due to their rapid kinetics and fast recovery from inactivation, A-type potassium channels (KA) are prime candidates for mediating this effect. AIM(S): The aim of our study was to assess whether the changes in neuronal excitability and response dynamics of CA1 pyramidal cells following the activation of 5-HT7 receptors are due to inhibition of A-type K+ channels. METHOD(S): Whole-cell patch-clamp recordings were performed in current-clamp mode. Neurons were held at −65 mV and their excitability was assessed using depolarizing current pulses. To activate 5-HT7 receptors, 5‑CT (250 nM) was applied along with WAY 100635 (2 µM), a 5-HT1A antagonist. Further recordings were performed in the presence of specific blockers of A‑type and H‑type channels. RESULTS: Activation of 5-HT7 receptors increased the excitability of CA1 pyramidal cells as well as decreased the latency to 1st spike, and effect which was prevented by using a specific Kv4.3/Kv4.4 channel blocker. Blockade of HCN channels did not affect the decrease in spike latency. CONCLUSIONS: Our data show that activation of 5-HT7 influences neuronal excitability in CA1 pyramidal cells partly by inhibiting fast-inactivating A-type potassium channels. These results help further explain the physiological role of the 5-HT7 receptor, hopefully leading to better understanding of its role in nervous system physiology and pathology. FINANCIAL SUPPORT: This study was supported by the Ministry of Science and Higher Education (Warsaw, Poland) grant no 2016/21/B/NZ4/03618 and statutory founds from the Department of Physiology, Institute of Pharmacology Polish Academy of Sciences, Krakow, Poland. J.E.S ans M.S. are beneficiaries of the KNOW PhD scholarship sponsored by the Ministry of Science and Higher Education, Poland.
EN
The amygdala is a part of the limbic system involved in emotional processing, which is highly connected with other areas of the brain. Its basolateral region (BLA) re‑ ceives many inputs, including those from prefrontal cor‑ tex, hippocampus, and thalamus. Moreover, the amygdala receives robust innervation from the raphe nuclei. The last serotonin receptor to be discovered, 5-HT7, is highly expressed in the amygdala, suggesting a possibly strong influence on amygdala function. The 5-HT7 receptor is involved in modulation of many physiological processes, such as learning, pain sensation, and mood regulation. Functions of the 5-HT7 receptor at the cellular and net‑ work level have been studied in the hippocampus, dorsal raphe nuclei, and frontal cortex. However, very little is known about the physiological role of 5-HT7 receptors in the amygdala. Our study aimed to elucidate the effect of 5-HT7 receptor activation on synaptic transmission, elec‑ trophysiological properties, and excitability of neurons in the BLA. Whole-cell patch-clamp recordings were made primarily from principal neurons in the BLA of mice, using acute brain slices(300 μm). Afterrecording a baseline, 5-CT (250 nM) in the presence of WAY 100635 (2 µM), a 5-HT1A receptor antagonist, was bath-applied. Both inhibitory and excitatory synaptic transmission were measured by recording spontaneous (sIPSC/sEPSC), miniature (mIPSC/ mEPSC) or evoked (eEPSC/eIPSC) postsynaptic currents. Moreover, excitability, input resistance, and membrane voltage were measured. Specificity of the observed effects was further investigated using the same experimental protocols with the 5-HT7 antagonist SB269970. Our results show an increase in excitability in fast-spiking interneu‑ rons in the amygdala. Regarding inhibitory transmission, 5-HT7 activation increased the amplitude and frequency of spontaneous, but not miniature, IPSC in the principal cells, which suggests that this effect was network-dependent. These effects were abolished in the presence of the 5-HT7 antagonist SB269970. Our data suggest that 5-HT7 activa‑ tion increases GABAergic synaptic transmission onto BLA principal neurons. This is probably due to increased GABA release from local interneurons, where 5-HT7 receptors may be localized. Together, these results suggest that the 5-HT7 receptor may act as a potent modulator of BLA in‑ hibitory transmission. Supported by National Science Cen‑ tre, grant 2016/21/B/NZ4/03618.
EN
The 5‑HT7 receptor has been implicated in mood reg‑ ulation, circadian rhythmicity, and sleep, the disturbances of which are evident in the course of depressive disorders. Research into 5‑HT7 receptor signalling in the hippocam‑ pus has indicated that activation of the 5‑HT7 receptor increases the excitability of pyramidal neurons of the CA1 and CA3 areas. The aim of our study was to investigate ionic mechanisms underlying this effect. We performed whole‑cell current clamp recordings from rat CA1 pyrami‑ dal cells and tested the effects of 5‑HT7 agonists on neu‑ ronal excitability and spiking dynamics. Voltage clamp recordings were used to determine changes in voltage‑de‑ pendent currents following 5‑HT7 receptor activation. Finally, we stimulated Schaffer collaterals and recorded evoked AMPA currents to examine whether these newly discovered ionic mechanisms influence synaptic transmis‑ sion. Administration of 5‑HT7 receptor agonists increased the excitability of CA1 pyramidal neurons, in line with pre‑ vious findings. This was accompanied by a significant de‑ crease in the time needed for the cell to fire the first action potential following a depolarizing current pulse. Voltage clamp recordings confirmed that 5‑HT7 receptor activation significantly attenuated the A‑type current. Pharmacolog‑ ical block of Kv4.2/4.3 channel subunits prevented the in‑ crease in neuronal excitability and spiking latency, as well as the 5‑HT7‑mediated increase in evoked AMPA current amplitude. In the present study we demonstrate that the 5‑HT7 receptor‑mediated effects on excitability, spiking latency and synaptic transmission are directly associated with inhibition of the A‑type potassium current, which is a mechanism not previously associated with this receptor.
EN
Hippocampal formation (HPC) theta rhythm is known to be one of the most synchronized EEG pat‑ terns in mammals. Theta field potentials in the HPC of rats are high‑amplitude, almost sinusoidal, waves in a 3‑12 Hz frequency range. It is well‑known that the posterior hypothalamic area (PHa including the supra‑ mammillary nucleus and posterior hypothalamic nuclei) is an important node in the pathway of HPC theta gen‑ eration, i.e. the ascending brainstem‑hippocampal syn‑ chronizing pathway. Furthermore, HPC theta frequency is at least partially modulated by the PHa through the activity of neurons firing in the frequency of HPC the‑ ta, at least during animals’ immobility‑related behav‑ iors. The PHa is thought to complement the activity of the medial septal area, widely known as the pacemaker of HPC theta rhythm. However, in our previous studies we discovered for the first time that cholinergic theta rhythm can also be recorded locally in deafferented pos‑ terior hypothalamic slices. Hence, in the present study we investigated PHa‑recorded theta‑related single cell activity in relation to local theta rhythm following ka‑ inic acid administration. 36 in vitro experiments were performed using brain slices (=72) taken from 36 adult Wistar rats. Each slice was perfused with 0.1 μM kain‑ ic acid to induce rhythmic activity and neuronal firing. Both field activity and corresponding cellular activity were recorded extracellularly. The relation of neuronal firing patterns to local field theta rhythm was investi‑ gated according to an existing universal classification of HPC theta‑related neurons. This study resulted in re‑ cording 17 theta‑related neurons and 77 neurons classi‑ fied as non‑related to local theta rhythm. A new neuron type (=21 cells) has been identified amongst the non‑re‑ lated group, which we termed timing cell, with a very rhythmic firing pattern in a nearly fixed frequency in the theta band. Kainate‑induced neuronal activity, re‑ corded in the posterior hypothalamic area in vitro, re‑ sembles cholinergically‑induced PHa neuronal activity, as well as well‑documented patterns of theta‑related cell discharges in the hippocampal formation in vitro and in vivo. Newly discovered PHa timing cells are discussed in light of an HPC theta rhythm frequency control mecha‑ nism. Supported by National Science Centre, Poland, No. UMO‑2017/25/B/NZ4/01476.
EN
INTRODUCTION: Theta rhythm is one of the brain rhythms’ patterns, which are evidence for neuronal synchrony. This pattern of rhythmic activity is related to sensorimotor integration, mnemonic functions, or spatial orientation and navigation. However, it is also linked to pathological conditions, for instance: Alzheimer’s disease, post‑traumatic stress disorder, and depression. In the last decade, we discovered that the posterior hypothalamic area (PHa) is not only a modulator of brainstem information going to the hippocampus, but also is capable of generating theta rhythm independently. AIM(S): The aim of the present study was to determine if NMDA (N-Methyl-D-aspartic acid) is capable of eliciting well-synchronized theta activity in PHa preparations. METHOD(S): The study was performed on 40 PHa slices prepared from 20 male Wistar rats. Each animal was anesthetized with isoflurane and decapitated. The PHa slices were dissected and transferred into the recording chamber, perfused with artificial cerebrospinal fluid, and treated with NMDA (300 µM) and D-AP5 (D‑(–)‑2‑amino‑5‑phosphonopentanoic acid) (200 µM). The field recordings were performed with glass electrodes filled with 2.0 M sodium acetate. RESULTS: Perfusions of PHa slices with 300 µM NMDA resulted in well-synchronized theta episodes which were blocked after the path application of 200 µM D‑AP5. CONCLUSIONS: The present data shows that excitation of NMDA-type glutamatergic receptors in PHa neural networks leads to the generation of local theta rhythms. FINANCIAL SUPPORT: Supported by NCN grant no. 2017/25/B/NZ4/01476.
EN
INTRODUCTION: Neuronal synchronization depends on many factors including HCN channel action. They are voltage-gated ion channels that mediate an inward cationic current dependent on hyperpolarization. There is sparse evidence for their contribution to neuronal plasticity, learning and memory, epilepsy, or Alzheimer’s disease. HCN channels can be found in the hippocampus (HPC) and are thought to be involved in neuronal synchronization through initiating membrane potential oscillations which are necessary for the appearance of field theta oscillations. Hippocampal theta rhythm is known to be involved in memory formation, spatial navigation, sensorimotor integration, movement initiation, and others. So far it is established that HPC theta generation is a result of a fine balance between the cholinergic and GABAergic system activation, which triggers the synchronous action of theta-related neurons. However, the involvement of HCN channels in this process is still mostly unknown. AIM(S): The aim of this study was to investigate the role of HCN channel activation in the process of theta generation. METHOD(S): Three experimental models were used: in vivo anesthetized rats, in vitro acute HPC slices, and HPC patch clamp whole cell method. Field and single neuron recordings were made from the HPC after perfusion with a non-specific HCN channels agonist – lamotrigine (LTG). RESULTS: When LTG was applied it produced mixed results. In particular, it blocked theta rhythm in vitro but significantly enhanced it in vivo. Patch clamp results have shown that LTG reduced the frequency of spontaneous inhibitory postsynaptic currents but also decreased the excitability and membrane resistance of CA1 neurons. Also, LTG reduced membrane potential theta resonance in most CA1 cells. CONCLUSIONS: HCN channels activation was shown to have an impact on the process of theta rhythm generation in the HPC. Current results are discussed. FINANCIAL SUPPORT: Supported by National Science Centre, grant no. 2017/26/D/NZ4/00159.
EN
INTRODUCTION: Theta rhythm typically occurs during memory processes, REM sleep, and spatial navigation but also in epilepsy, migraines, or even mild Alzheimer’s disease (AD). Recent evidence shows that well-synchronized theta rhythm can successfully be recorded locally from the posterior hypothalamic area (PHa), specifically from the supramammillary nucleus (SuM) and the posterior hypothalamic nuclei (PH). The population of theta-related cells in the PHa were found to be similar types to those found in the hippocampal formation. In addition, a new type of cells has been found in the posterior hypothalamic region and based on its regular firing pattern and possible pacemaker role these cells were termed “timing”. AIM(S): The aim of the present study was to investigate the timing of cell populations in both in vivo and in vitro PHa after theta rhythm induction by kainic acid (KA) application. METHOD(S): Twenty in vivo experiments were performed on 20 urethanized rats and 22 in vitro experiments were performed on 40 PHa slices obtained from 22 rats. Theta rhythm and single unit activity were evoked by intra-PHa microinjection of KA (in vivo) or by bath perfusion of PHa slices with KA-containing artificial cerebrospinal fluid (in vitro). RESULTS: A total number of 123 posterior hypothalamic neurons were recorded during both in vivo and in vitro experiments. Among them, 28 neurons were classified as “timing cells” according to their very regular pattern of discharges in a steady frequency in the theta band (3‑12 Hz). Eight timing cells were recorded in in vivo PHa and 20 timing cells were recorded in PHa slices. CONCLUSIONS: The present data show that glutamatergic stimulation of PHa neuronal network with kainic acid results in the activation of specific subpopulation of neutrons, characterized by regular firing pattern in theta frequency range. The role of PHa “timing cell” activity is discussed regarding hippocampal theta rhythm frequency programing. FINANCIAL SUPPORT: Supported by NCN grant No. 2017/25/B/NZ4/01476.
EN
INTRODUCTION: The amygdala mediates unconscious reactions and is responsible for emotional memory formation and attachment of subjective emotional valence to various stimuli. The amygdala complex expresses 5-HT7 receptors in a high density, however, their function in this structure remains poorly investigated. AIM(S): The present experiments were aimed at determining the effects of 5-HT7 receptor activation on membrane properties and synaptic transmission in pyramidal‑like basal amygdala (BA) neurons. METHOD(S): Whole-cell patch clamp recordings were performed on the brain slices containing a part of the amygdala. Spontaneous excitatory and miniature postsynaptic currents (sEPSCs and mEPSCs) were recorded at a holding potential of ‑70 mV. Spontaneous and miniature inhibitory postsynaptic currents (sIPSCs and mIPSCs) were recorded at a holding potential of 0 mV with pipette filled with cesium gluconate-containing solution. RESULTS: Activation of 5-HT7 receptors decreased the mean frequency of sEPSCs without changing sEPSCs amplitude. The mean frequency and amplitude of sIPSCs were enhanced after 5-HT7 receptor activation. Administration of 5-HT7 receptors agonist 5-CT induced a hyperpolarization and an increase of the membrane resistance in a majority of recorded cells. The frequency and amplitude of mEPSCs and mIPSCs were not changed after 5‑CT administration. The observed effects of 5‑HT7 receptors activation were absent in the presence of the 5-HT7 receptor antagonist SB 269970. The application of 5-CT had no effect in slices prepared from 5-HT7 knockout mice. CONCLUSIONS: These data suggest that the observed decrease in sEPSCs and an increase in sIPSCs frequency and amplitude result from activation of 5-HT7 receptors located on GABAergic interneurons that, in turn, innervate BA projection neurons. FINANCIAL SUPPORT: Supported by grant 2016/21/B/NZ4/03618 financed by the National Science Center, Poland, and by statutory funds from Maj Institute of Pharmacology, Polish Academy of Sciences.
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