1
|
Csemer A, Sokvári C, Maamrah B, Szabó L, Korpás K, Pocsai K, Pál B. Pharmacological Activation of Piezo1 Channels Enhances Astrocyte-Neuron Communication via NMDA Receptors in the Murine Neocortex. Int J Mol Sci 2024; 25:3994. [PMID: 38612801 PMCID: PMC11012114 DOI: 10.3390/ijms25073994] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/21/2024] [Revised: 03/28/2024] [Accepted: 03/30/2024] [Indexed: 04/14/2024] Open
Abstract
The Piezo1 mechanosensitive ion channel is abundant on several elements of the central nervous system including astrocytes. It has been already demonstrated that activation of these channels is able to elicit calcium waves on astrocytes, which contributes to the release of gliotransmitters. Astrocyte- and N-methyl-D-aspartate (NMDA) receptor-dependent slow inward currents (SICs) are hallmarks of astrocyte-neuron communication. These currents are triggered by glutamate released as gliotransmitter, which in turn activates neuronal NMDA receptors responsible for this inward current having slower kinetics than any synaptic events. In this project, we aimed to investigate whether Piezo1 activation and inhibition is able to alter spontaneous SIC activity of murine neocortical pyramidal neurons. When the Piezo1 opener Yoda1 was applied, the SIC frequency and the charge transfer by these events in a minute time was significantly increased. These changes were prevented by treating the preparations with the NMDA receptor inhibitor D-AP5. Furthermore, Yoda1 did not alter the spontaneous EPSC frequency and amplitude when SICs were absent. The Piezo1 inhibitor Dooku1 effectively reverted the actions of Yoda1 and decreased the rise time of SICs when applied alone. In conclusion, activation of Piezo1 channels is able to alter astrocyte-neuron communication. Via enhancement of SIC activity, astrocytic Piezo1 channels have the capacity to determine neuronal excitability.
Collapse
Affiliation(s)
- Andrea Csemer
- Department of Physiology, Faculty of Medicine, University of Debrecen, H-4002 Debrecen, Hungary; (A.C.); (C.S.); (B.M.); (K.K.); (K.P.)
- Doctoral School of Molecular Medicine, University of Debrecen, H-4012 Debrecen, Hungary;
| | - Cintia Sokvári
- Department of Physiology, Faculty of Medicine, University of Debrecen, H-4002 Debrecen, Hungary; (A.C.); (C.S.); (B.M.); (K.K.); (K.P.)
- Doctoral School of Molecular Medicine, University of Debrecen, H-4012 Debrecen, Hungary;
| | - Baneen Maamrah
- Department of Physiology, Faculty of Medicine, University of Debrecen, H-4002 Debrecen, Hungary; (A.C.); (C.S.); (B.M.); (K.K.); (K.P.)
- Doctoral School of Molecular Medicine, University of Debrecen, H-4012 Debrecen, Hungary;
| | - László Szabó
- Doctoral School of Molecular Medicine, University of Debrecen, H-4012 Debrecen, Hungary;
- HUN-REN DE Cell Physiology Research Group, H-4032 Debrecen, Hungary
| | - Kristóf Korpás
- Department of Physiology, Faculty of Medicine, University of Debrecen, H-4002 Debrecen, Hungary; (A.C.); (C.S.); (B.M.); (K.K.); (K.P.)
- Doctoral School of Molecular Medicine, University of Debrecen, H-4012 Debrecen, Hungary;
| | - Krisztina Pocsai
- Department of Physiology, Faculty of Medicine, University of Debrecen, H-4002 Debrecen, Hungary; (A.C.); (C.S.); (B.M.); (K.K.); (K.P.)
| | - Balázs Pál
- Department of Physiology, Faculty of Medicine, University of Debrecen, H-4002 Debrecen, Hungary; (A.C.); (C.S.); (B.M.); (K.K.); (K.P.)
- Doctoral School of Molecular Medicine, University of Debrecen, H-4012 Debrecen, Hungary;
| |
Collapse
|
2
|
Csemer A, Kovács A, Maamrah B, Pocsai K, Korpás K, Klekner Á, Szücs P, Nánási PP, Pál B. Astrocyte- and NMDA receptor-dependent slow inward currents differently contribute to synaptic plasticity in an age-dependent manner in mouse and human neocortex. Aging Cell 2023; 22:e13939. [PMID: 37489544 PMCID: PMC10497838 DOI: 10.1111/acel.13939] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/06/2022] [Revised: 07/12/2023] [Accepted: 07/14/2023] [Indexed: 07/26/2023] Open
Abstract
Slow inward currents (SICs) are known as excitatory events of neurons elicited by astrocytic glutamate via activation of extrasynaptic NMDA receptors. By using slice electrophysiology, we tried to provide evidence that SICs can elicit synaptic plasticity. Age dependence of SICs and their impact on synaptic plasticity was also investigated in both on murine and human cortical slices. It was found that SICs can induce a moderate synaptic plasticity, with features similar to spike timing-dependent plasticity. Overall SIC activity showed a clear decline with aging in humans and completely disappeared above a cutoff age. In conclusion, while SICs contribute to a form of astrocyte-dependent synaptic plasticity both in mice and humans, this plasticity is differentially affected by aging. Thus, SICs are likely to play an important role in age-dependent physiological and pathological alterations of synaptic plasticity.
Collapse
Affiliation(s)
- Andrea Csemer
- Department of Physiology, Faculty of MedicineUniversity of DebrecenDebrecenHungary
- Doctoral School of Molecular MedicineUniversity of DebrecenDebrecenHungary
| | - Adrienn Kovács
- Department of Physiology, Faculty of MedicineUniversity of DebrecenDebrecenHungary
| | - Baneen Maamrah
- Department of Physiology, Faculty of MedicineUniversity of DebrecenDebrecenHungary
- Doctoral School of Molecular MedicineUniversity of DebrecenDebrecenHungary
| | - Krisztina Pocsai
- Department of Physiology, Faculty of MedicineUniversity of DebrecenDebrecenHungary
| | - Kristóf Korpás
- Department of Physiology, Faculty of MedicineUniversity of DebrecenDebrecenHungary
| | - Álmos Klekner
- Department of Neurosurgery, Clinical CentreUniversity of DebrecenDebrecenHungary
| | - Péter Szücs
- Department of Anatomy, Histology and Embryology, Faculty of MedicineUniversity of DebrecenDebrecenHungary
| | - Péter P. Nánási
- Department of Physiology, Faculty of MedicineUniversity of DebrecenDebrecenHungary
- Department of Dental Physiology and Pharmacology, Faculty of DentistryUniversity of DebrecenDebrecenHungary
| | - Balázs Pál
- Department of Physiology, Faculty of MedicineUniversity of DebrecenDebrecenHungary
- Doctoral School of Molecular MedicineUniversity of DebrecenDebrecenHungary
| |
Collapse
|
3
|
Maamrah B, Pocsai K, Bayasgalan T, Csemer A, Pál B. KCNQ4 potassium channel subunit deletion leads to exaggerated acoustic startle reflex in mice. Neuroreport 2023; 34:232-237. [PMID: 36789839 PMCID: PMC10399928 DOI: 10.1097/wnr.0000000000001883] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/20/2022] [Accepted: 01/06/2023] [Indexed: 02/16/2023]
Abstract
The potassium voltage-gated channel subfamily Q member 4 (KCNQ4) subunit forms channels responsible for M-current, a muscarine-sensitive potassium current regulating neuronal excitability. In contrast to other KCNQ subunits, its expression is restricted to the cochlear outer hair cells, the auditory brainstem and other brainstem nuclei in a great overlap with structures involved in startle reflex. We aimed to show whether startle reflexis affected by the loss of KCNQ4 subunit and whether these alterations are similar to the ones caused by brainstem hyperexcitability. Young adult KCNQ4 knockout mice and wild-type littermates, as well as mice expressing hM3D chemogenetic actuator in the pontine caudal nucleus and neurons innervating it were used for testing acoustic startle. The acoustic startle reflex was significantly increased in knockout mice compared with wild-type littermates. When mice expressing human M3 muscarinic (hM3D) in nuclei related to startle reflex were tested, a similar increase of the first acoustic startle amplitude and a strong habituation of the further responses was demonstrated. We found that the acoustic startle reflex is exaggerated and minimal habituation occurs in KCNQ4 knockout animals. These changes are distinct from the effects of the hyperexcitability of nuclei involved in startle. One can conclude that the exaggerated startle reflex found with the KCNQ4 subunit deletion is the consequence of both the cochlear damage and the changes in neuronal excitability of startle networks.
Collapse
Affiliation(s)
- Baneen Maamrah
- Department of Physiology, Faculty of Medicine, University of Debrecen
- Doctoral School of Molecular Medicine, University of Debrecen, Debrecen, Hungary
| | - Krisztina Pocsai
- Department of Physiology, Faculty of Medicine, University of Debrecen
| | - Tsogbadrakh Bayasgalan
- Department of Physiology, Faculty of Medicine, University of Debrecen
- Doctoral School of Molecular Medicine, University of Debrecen, Debrecen, Hungary
- Center for Molecular and Behavioral Neuroscience, Rutgers University, Newark, New Jersey, USA
| | - Andrea Csemer
- Department of Physiology, Faculty of Medicine, University of Debrecen
| | - Balázs Pál
- Department of Physiology, Faculty of Medicine, University of Debrecen
| |
Collapse
|
4
|
Bayasgalan T, Stupniki S, Kovács A, Csemer A, Szentesi P, Pocsai K, Dionisio L, Spitzmaul G, Pál B. Alteration of Mesopontine Cholinergic Function by the Lack of KCNQ4 Subunit. Front Cell Neurosci 2021; 15:707789. [PMID: 34381336 PMCID: PMC8352570 DOI: 10.3389/fncel.2021.707789] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/10/2021] [Accepted: 06/28/2021] [Indexed: 11/16/2022] Open
Abstract
The pedunculopontine nucleus (PPN), a structure known as a cholinergic member of the reticular activating system (RAS), is source and target of cholinergic neuromodulation and contributes to the regulation of the sleep–wakefulness cycle. The M-current is a voltage-gated potassium current modulated mainly by cholinergic signaling. KCNQ subunits ensemble into ion channels responsible for the M-current. In the central nervous system, KCNQ4 expression is restricted to certain brainstem structures such as the RAS nuclei. Here, we investigated the presence and functional significance of KCNQ4 in the PPN by behavioral studies and the gene and protein expressions and slice electrophysiology using a mouse model lacking KCNQ4 expression. We found that this mouse has alterations in the adaptation to changes in light–darkness cycles, representing the potential role of KCNQ4 in the regulation of the sleep–wakefulness cycle. As cholinergic neurons from the PPN participate in the regulation of this cycle, we investigated whether the cholinergic PPN might also possess functional KCNQ4 subunits. Although the M-current is an electrophysiological hallmark of cholinergic neurons, only a subpopulation of them had KCNQ4-dependent M-current. Interestingly, the absence of the KCNQ4 subunit altered the expression patterns of the other KCNQ subunits in the PPN. We also determined that, in wild-type animals, the cholinergic inputs of the PPN modulated the M-current, and these in turn can modulate the level of synchronization between neighboring PPN neurons. Taken together, the KCNQ4 subunit is present in a subpopulation of PPN cholinergic neurons, and it may contribute to the regulation of the sleep–wakefulness cycle.
Collapse
Affiliation(s)
- T Bayasgalan
- Department of Physiology, Faculty of Medicine, University of Debrecen, Debrecen, Hungary
| | - S Stupniki
- Instituto de Investigaciones Bioquímicas de Bahía Blanca (INIBIBB), Consejo Nacional de Investigaciones Científicas y Técnicas (CONICET), Universidad Nacional Del Sur (UNS), Bahía Blanca, Argentina.,Departamento de Biología, Bioquímica y Farmacia, Universidad Nacional del Sur, Bahía Blanca, Argentina
| | - A Kovács
- Department of Physiology, Faculty of Medicine, University of Debrecen, Debrecen, Hungary
| | - A Csemer
- Department of Physiology, Faculty of Medicine, University of Debrecen, Debrecen, Hungary
| | - P Szentesi
- Department of Physiology, Faculty of Medicine, University of Debrecen, Debrecen, Hungary
| | - K Pocsai
- Department of Physiology, Faculty of Medicine, University of Debrecen, Debrecen, Hungary
| | - L Dionisio
- Instituto de Investigaciones Bioquímicas de Bahía Blanca (INIBIBB), Consejo Nacional de Investigaciones Científicas y Técnicas (CONICET), Universidad Nacional Del Sur (UNS), Bahía Blanca, Argentina.,Departamento de Biología, Bioquímica y Farmacia, Universidad Nacional del Sur, Bahía Blanca, Argentina
| | - G Spitzmaul
- Instituto de Investigaciones Bioquímicas de Bahía Blanca (INIBIBB), Consejo Nacional de Investigaciones Científicas y Técnicas (CONICET), Universidad Nacional Del Sur (UNS), Bahía Blanca, Argentina.,Departamento de Biología, Bioquímica y Farmacia, Universidad Nacional del Sur, Bahía Blanca, Argentina
| | - B Pál
- Department of Physiology, Faculty of Medicine, University of Debrecen, Debrecen, Hungary
| |
Collapse
|
5
|
Bayasgalan T, Csemer A, Kovacs A, Pocsai K, Pal B. Topographical Organization of M-Current on Dorsal and Median Raphe Serotonergic Neurons. Front Cell Neurosci 2021; 15:614947. [PMID: 33716672 PMCID: PMC7947297 DOI: 10.3389/fncel.2021.614947] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/07/2020] [Accepted: 01/28/2021] [Indexed: 11/13/2022] Open
Abstract
Dorsal and median raphe nuclei (DR and MR, respectively) are members of the reticular activating system and play important role in the regulation of the sleep-wakefulness cycle, movement, and affective states. M-current is a voltage-gated potassium current under the control of neuromodulatory mechanisms setting neuronal excitability. Our goal was to determine the proportion of DR and MR serotonergic neurons possessing M-current and whether they are organized topographically. Electrophysiological parameters of raphe serotonergic neurons influenced by this current were also investigated. We performed slice electrophysiology on genetically identified serotonergic neurons. Neurons with M-current are located rostrally in the DR and dorsally in the MR. M-current determines firing rate, afterhyperpolarization amplitude, and adaptation index (AI) of these neurons, but does not affect input resistance, action potential width, and high threshold oscillations.These findings indicate that M-current has a strong impact on firing properties of certain serotonergic neuronal subpopulations and it might serve as an effective contributor to cholinergic and local serotonergic neuromodulatory actions.
Collapse
Affiliation(s)
- Tsogbadrakh Bayasgalan
- Department of Physiology, Faculty of Medicine, University of Debrecen, Debrecen, Hungary
| | - Andrea Csemer
- Department of Physiology, Faculty of Medicine, University of Debrecen, Debrecen, Hungary
| | - Adrienn Kovacs
- Department of Physiology, Faculty of Medicine, University of Debrecen, Debrecen, Hungary
| | - Krisztina Pocsai
- Department of Physiology, Faculty of Medicine, University of Debrecen, Debrecen, Hungary
| | - Balazs Pal
- Department of Physiology, Faculty of Medicine, University of Debrecen, Debrecen, Hungary
| |
Collapse
|
6
|
Bencze J, Pocsai K, Murnyák B, Gergely PA, Juhász B, Szilvássy Z, Hortobágyi T. The Melanin-concentrating Hormone System in Human, Rodent and Avian Brain. Open Med (Wars) 2018; 13:264-269. [PMID: 29992190 PMCID: PMC6034100 DOI: 10.1515/med-2018-0040] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/06/2018] [Accepted: 05/06/2018] [Indexed: 12/20/2022] Open
Abstract
Melanin-concentrating hormone (MCH) is a cyclic 19 amino acid orexigenic hypothalamic peptide. MCH is located in the lateral and dorsal hypothalamus, as well as in the zona incerta. In mammals MCH increases food intake, contributes to regulation of energy balance, temperature, reproductive function, endocrine homeostasis and biological rhythms. Several studies have proved the significance of MCH in obesity, diabetes and depression. Although the peptide is well-characterized in mouse models, much less is known about its functions in avians. In birds the MCH system especially in the lateral and basal hypothalamus has important connections to the limbic system and it coordinates the vegetative and endocrine functions, as well as the emotional behaviour. Pharmacological modulation of MCH system could contribute to the therapy of eating disorders and improve agricultural efficiency regarding avians. Reviewing the current knowledge on MCH system in human, rodents and avians may stimulate a new wave of studies in the field.
Collapse
Affiliation(s)
- János Bencze
- Division of Neuropathology, Institute of Pathology, Faculty of Medicine, University of Debrecen, Debrecen, Hungary
| | - Krisztina Pocsai
- Division of Neuropathology, Institute of Pathology, Faculty of Medicine, University of Debrecen, Debrecen, Hungary
| | - Balázs Murnyák
- MTA-DE Cerebrovascular and Neurodegenerative Research Group, Debrecen, Hungary.,Division of Neuropathology, Institute of Pathology, Faculty of Medicine, University of Debrecen, Debrecen, Hungary
| | - Péter Attila Gergely
- Department of Forensic Medicine, Faculty of Medicine, University of Debrecen, Debrecen, Hungary
| | - Béla Juhász
- Department of Pharmacology and Pharmacotherapy, University of Debrecen, Debrecen, Hungary
| | - Zoltán Szilvássy
- Department of Pharmacology and Pharmacotherapy, University of Debrecen, Debrecen, Hungary
| | - Tibor Hortobágyi
- Division of Neuropathology, Institute of Pathology, Faculty of Medicine, University of Debrecen, Debrecen, Nagyerdei krt. 98., H-4032, Hungary.,Department of Pathology, Faculty of Medicine, University of Szeged, Szeged, Hungary.,Department of Old Age Psychiatry, Institute of Psychiatry Psychology & Neuroscience, King's College London, London, UK.,MTA-DE Cerebrovascular and Neurodegenerative Research Group, Debrecen, Hungary
| |
Collapse
|
7
|
Kyrychenko S, Poláková E, Kang C, Pocsai K, Ullrich ND, Niggli E, Shirokova N. Hierarchical accumulation of RyR post-translational modifications drives disease progression in dystrophic cardiomyopathy. Cardiovasc Res 2012; 97:666-75. [PMID: 23263329 DOI: 10.1093/cvr/cvs425] [Citation(s) in RCA: 39] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
AIMS Duchenne muscular dystrophy (DMD) is a muscle disease with serious cardiac complications. Changes in Ca(2+) homeostasis and oxidative stress were recently associated with cardiac deterioration, but the cellular pathophysiological mechanisms remain elusive. We investigated whether the activity of ryanodine receptor (RyR) Ca(2+) release channels is affected, whether changes in function are cause or consequence and which post-translational modifications drive disease progression. METHODS AND RESULTS Electrophysiological, imaging, and biochemical techniques were used to study RyRs in cardiomyocytes from mdx mice, an animal model of DMD. Young mdx mice show no changes in cardiac performance, but do so after ∼8 months. Nevertheless, myocytes from mdx pups exhibited exaggerated Ca(2+) responses to mechanical stress and 'hypersensitive' excitation-contraction coupling, hallmarks of increased RyR Ca(2+) sensitivity. Both were normalized by antioxidants, inhibitors of NAD(P)H oxidase and CaMKII, but not by NO synthases and PKA antagonists. Sarcoplasmic reticulum Ca(2+) load and leak were unchanged in young mdx mice. However, by the age of 4-5 months and in senescence, leak was increased and load was reduced, indicating disease progression. By this age, all pharmacological interventions listed above normalized Ca(2+) signals and corrected changes in ECC, Ca(2+) load, and leak. CONCLUSION Our findings suggest that increased RyR Ca(2+) sensitivity precedes and presumably drives the progression of dystrophic cardiomyopathy, with oxidative stress initiating its development. RyR oxidation followed by phosphorylation, first by CaMKII and later by PKA, synergistically contributes to cardiac deterioration.
Collapse
Affiliation(s)
- Sergii Kyrychenko
- Department of Pharmacology and Physiology, New Jersey Medical School, 185 S. Orange Ave., Newark, NJ 07103, USA
| | | | | | | | | | | | | |
Collapse
|
8
|
Fanchaouy M, Pocsai K, Shirokova N, Niggli E. Redox Modifications of Ca2+-Release Events in Cardiomyocytes. Biophys J 2010. [DOI: 10.1016/j.bpj.2009.12.2975] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022] Open
|
9
|
Pál B, Koszeghy A, Pap P, Bakondi G, Pocsai K, Szucs G, Rusznák Z. Targets, receptors and effects of muscarinic neuromodulation on giant neurones of the rat dorsal cochlear nucleus. Eur J Neurosci 2009; 30:769-82. [PMID: 19712095 DOI: 10.1111/j.1460-9568.2009.06868.x] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
Abstract
Although cholinergic modulation of the cochlear nucleus (CN) is functionally important, neither its cellular consequences nor the types of receptors conveying it are precisely known. The aim of this work was to characterise the cholinergic effects on giant cells of the CN, using electrophysiology and quantitative polymerase chain reaction. Application of the cholinergic agonist carbachol increased the spontaneous activity of the giant cells; which was partly the consequence of the reduction in a K(+) conductance. This effect was mediated via M4 and M3 receptors. Cholinergic modulation also affected the synaptic transmission targeting the giant cells. Excitatory synaptic currents evoked by the stimulation of the superficial and deep regions of the CN were sensitive to cholinergic modulation: the amplitude of the first postsynaptic current was reduced, and the short-term depression was also altered. These changes were mediated via M3 receptors alone and via the combination of M4, M2 and M3 receptors, when the superficial and deep layers, respectively, were activated. Inhibitory synaptic currents evoked from the superficial layer showed short-term depression, but they were unaffected by carbachol. In contrast, inhibitory currents triggered by the activation of the deep parts exhibited no significant short-term depression, but they were highly sensitive to cholinergic activation, which was mediated via M3 receptors. Our results indicate that pre- and postsynaptic muscarinic receptors mediate cholinergic modulation on giant cells. The present findings shed light on the cellular mechanisms of a tonic cholinergic modulation in the CN, which may become particularly important in evoking contralateral excitatory responses under certain pathological conditions.
Collapse
Affiliation(s)
- B Pál
- Department of Physiology, Medical and Health Science Centre, University of Debrecen, Debrecen, Hungary.
| | | | | | | | | | | | | |
Collapse
|
10
|
Koszeghy A, Pál B, Pap P, Pocsai K, Nagy Z, Szucs G, Rusznák Z. Purkinje-like cells of the rat cochlear nucleus: a combined functional and morphological study. Brain Res 2009; 1297:57-69. [PMID: 19699723 DOI: 10.1016/j.brainres.2009.08.041] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/05/2009] [Revised: 08/11/2009] [Accepted: 08/13/2009] [Indexed: 10/20/2022]
Abstract
Purkinje-like cells (PLCs) of the cochlear nucleus (CN) are strongly calbindin positive neurones with unknown function. In the present work functional and morphological methods have been employed to provide data about PLCs in general, and about their possible involvement in the synaptic organisation of the CN in particular. PLCs had slightly elongated soma, from which a complex dendritic arborisation extended with highly variable dimensions. On the basis of their morphology, three classes of PLCs were identified. Positively identified PLCs fired a train of action potentials on sustained depolarization. When hyperpolarizing stimuli were applied, the presence of a slowly activating, ZD7288-sensitive inward current was noted that corresponded to the h-current. PLCs received both excitatory and inhibitory synaptic inputs. Functional experiments revealed that 76% and 14% of the spontaneous inhibitory postsynaptic currents recorded from the cell bodies of the PLCs were mediated via glycinergic and GABAergic synapses, respectively. PLCs presented strong cerebellin1-like immunoreactivity, but its distribution differed from that seen in cerebellar Purkinje cells. Our results indicate that PLCs are parts of the synaptic circuitry of the CN, thus they may be actively involved in the processing and analysis of auditory information.
Collapse
Affiliation(s)
- Aron Koszeghy
- Department of Physiology, RCMM, Medical and Health Science Centre, University of Debrecen, P.O. Box 22, H-4012 Debrecen, Hungary
| | | | | | | | | | | | | |
Collapse
|
11
|
Rusznák Z, Bakondi G, Pocsai K, Pór A, Kosztka L, Pál B, Nagy D, Szucs G. Voltage-gated potassium channel (Kv) subunits expressed in the rat cochlear nucleus. J Histochem Cytochem 2008; 56:443-65. [PMID: 18256021 PMCID: PMC2324191 DOI: 10.1369/jhc.2008.950303] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
Because the neuronal membrane properties and firing characteristics are crucially affected by the depolarization-activated K(+) channel (Kv) subunits, data about the Kv distribution may provide useful information regarding the functionality of the neurons situated in the cochlear nucleus (CN). Using immunohistochemistry in free-floating slices, the distribution of seven Kv subunits was described in the rat CN. Positive labeling was observed for Kv1.1, 1.2, 1.6, 3.1, 3.4, 4.2, and 4.3 subunits. Giant and octopus neurons showed particularly strong immunopositivity for Kv3.1; octopus neurons showed intense Kv1.1- and 1.2-specific reactions also. In the latter case, an age-dependent change of the expression pattern was also documented; although both young and older animals produced definite labeling for Kv1.2, the intensity of the reaction increased in older animals and was accompanied with the translocation of the Kv1.2 subunits to the cell surface membrane. The granule cell layer exhibited strong Kv4.2-specific immunopositivity, and markedly Kv4.2-positive glomerular synapses were also seen. It was found that neither giant nor pyramidal cells were uniform in terms of their Kv expression patterns. Our data provide new information about the Kv expression of the CN and also suggest potential functional heterogeneity of the giant and pyramidal cells.
Collapse
Affiliation(s)
- Zoltán Rusznák
- Department of Physiology, Medical and Health Science Centre, University of Debrecen, PO Box 22, H-4012 Debrecen, Hungary
| | | | | | | | | | | | | | | |
Collapse
|
12
|
Rusznák Z, Bakondi G, Kosztka L, Pocsai K, Dienes B, Fodor J, Telek A, Gönczi M, Szűcs G, Csernoch L. Mitochondrial expression of the two-pore domain TASK-3 channels in malignantly transformed and non-malignant human cells. Virchows Arch 2007; 452:415-26. [DOI: 10.1007/s00428-007-0545-x] [Citation(s) in RCA: 63] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/17/2007] [Revised: 10/20/2007] [Accepted: 10/31/2007] [Indexed: 11/30/2022]
|
13
|
Pocsai K, Pál B, Pap P, Bakondi G, Kosztka L, Rusznák Z, Szucs G. Rhodamine backfilling and confocal microscopy as a tool for the unambiguous identification of neuronal cell types: a study of the neurones of the rat cochlear nucleus. Brain Res Bull 2006; 71:529-38. [PMID: 17259023 DOI: 10.1016/j.brainresbull.2006.11.009] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/26/2006] [Revised: 10/17/2006] [Accepted: 11/19/2006] [Indexed: 10/23/2022]
Abstract
Adequate interpretation of the functional data characterising the projection neurones of the cochlear nucleus (CN) is impossible without the unequivocal classification of these cell types at the end of the experiments. In this study, morphological criteria applicable for unambiguous identification of CN neurones have been sought. The neurones were labelled with rhodamine from incisions severing the projection pathways of the individual cell types, allowing their selective labelling and morphological characterisation. Confocal microscopy was employed for the investigation of the rhodamine-filled cells whose morphology was assessed after reconstructing the three-dimensional images of the cell bodies and proximal processes. The diameters of the somata and the number of processes originating from the cell bodies were also determined. In most of the cases, unambiguous identification of the bushy, octopus and Purkinje-like cells was relatively straightforward. On the other hand, precise classification of the pyramidal cells was often difficult, especially because giant cells could easily possess morphological features resembling pyramidal neurones. Occasionally, giant cells also mimicked the appearance of octopus neurones, which may be another important source of identification error, especially as these two cell types are often situated close to each other in the CN. It is concluded that morphological criteria defined in the present work may be effectively applied for the unambiguous identification of the projection neurones of the CN, even following functional measurements, when the correct cell classification is essential for the interpretation of the experimental data. Moreover, the present study also confirmed that Purkinje-like cells project to the cerebellum.
Collapse
Affiliation(s)
- Krisztina Pocsai
- Department of Physiology, Medical and Health Science Centre, University of Debrecen, PO Box 22, H-4012 Debrecen, Hungary
| | | | | | | | | | | | | |
Collapse
|
14
|
Pocsai K, Kosztka L, Bakondi G, Gönczi M, Fodor J, Dienes B, Szentesi P, Kovács I, Feniger-Barish R, Kopf E, Zharhary D, Szucs G, Csernoch L, Rusznák Z. Melanoma cells exhibit strong intracellular TASK-3-specific immunopositivity in both tissue sections and cell culture. Cell Mol Life Sci 2006; 63:2364-76. [PMID: 17013562 DOI: 10.1007/s00018-006-6166-8] [Citation(s) in RCA: 26] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/24/2022]
Abstract
Amplification of the kcnk9 gene and overexpression of the encoded channel protein (TASK-3) seems to be involved in carcinogenesis. In the present work, TASK-3 expression of melanoma cells has been studied. For the investigation of TASK-3-specific immunolabelling, a monoclonal antibody has been developed and applied along with two, commercially available polyclonal antibodies targeting different epitopes of the channel protein. Both primary and metastatic melanoma cells proved to be TASK-3 positive, showing prominent intracellular TASK-3-specific labelling; mostly concentrating around or in the proximity of the nuclei. The immunoreaction was associated with the nuclear envelope, and with the processes of the cells and it was also present in the cell surface membrane. Specificity of the immunolabelling was confirmed by Western blot and transfection experiments. As TASK-3 immunopositivity of benign melanocytes could also be demonstrated, the presence or absence of TASK-3 channels cannot differentiate between malignant and non-malignant melanocytic tumours.
Collapse
Affiliation(s)
- K Pocsai
- Department of Physiology, RCMM, Medical and Health Science Centre, University of Debrecen, P.O. Box 22, 4012, Debrecen, Hungary
| | | | | | | | | | | | | | | | | | | | | | | | | | | |
Collapse
|
15
|
Pór A, Pocsai K, Rusznák Z, Szucs G. Presence and distribution of three calcium binding proteins in projection neurons of the adult rat cochlear nucleus. Brain Res 2005; 1039:63-74. [PMID: 15781047 DOI: 10.1016/j.brainres.2005.01.057] [Citation(s) in RCA: 29] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/22/2004] [Revised: 01/12/2005] [Accepted: 01/12/2005] [Indexed: 11/24/2022]
Abstract
The presence and distribution of three cytoplasmic calcium binding proteins, calbindin, calretinin, and parvalbumin, have been investigated in the projection neurons of the cochlear nucleus complex in adult rats by using immunohistochemistry in free-floating slices. Identification of the individual cell types was carried out on the basis of their intranuclear localization, morphological characteristics, and (in the cases of pyramidal and bushy neurons) by retrograde labeling with rhodamine-dextran. The most important findings were confirmed by using confocal microscopy. The data obtained in these experiments are the first to demonstrate the presence of parvalbumin in pyramidal neurons and globular and spherical bushy cells of rat cochlear nucleus, whereas octopus and giant cells did not show positivity for parvalbumin. Calretinin was not present in either Purkinje-like cells or giant neurons. According to the double immunolabeling co-localization experiments, the pyramidal neurons, Purkinje-like cells, globular bushy cells, and octopus cells express two different calcium binding proteins in their cytoplasm (although in different combinations) whereas giant cells and spherical bushy cells contain solely calbindin and parvalbumin, respectively. The presence of calretinin in globular bushy cells provides a tool for distinguishing them from spherical bushy cells. The immunolabeling of the fibers and axonal endings of the acoustic nerve in the ventral part of the cochlear nucleus indicated that these structures are also parvalbumin positive. It is concluded that the heterogenous cell composition of the cochlear nucleus is accompanied by a rather complex expression pattern of the cytoplasmic calcium binding proteins.
Collapse
Affiliation(s)
- Agnes Pór
- Department of Physiology, Medical and Health Science Center, University of Debrecen, PO Box 22, H-4012 Debrecen, Hungary
| | | | | | | |
Collapse
|
16
|
Kovács I, Pocsai K, Czifra G, Sarkadi L, Szucs G, Nemes Z, Rusznák Z. TASK-3 immunoreactivity shows differential distribution in the human gastrointestinal tract. Virchows Arch 2005; 446:402-10. [PMID: 15789217 DOI: 10.1007/s00428-005-1205-7] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/29/2004] [Accepted: 12/15/2004] [Indexed: 11/26/2022]
Abstract
The presence and distribution of TASK-3 immunopositivity (a channel with potential oncogenic significance) was investigated in the human gastrointestinal system. The immunohistochemical reactions were performed with two commercially available polyclonal antibodies, targeting different epitopes of the channel protein. Experiments conducted on frozen and formalin-fixed samples indicated that the application of a suitable antigen retrieval (AR) technique was essential to produce consistent, strong and reproducible TASK-3-specific immunolabelling of the formalin-fixed tissue. The lack of or inappropriate selection of the AR resulted in false-negative reactions. As for the distribution of the TASK-3 channels, strong immunolabelling was observed in the gastric and large intestinal mucosa, with particularly prominent immunoreactivity of the epithelial cells. In contrast, the smooth-muscle layers demonstrated weak TASK-3 positivity. Intense TASK-3 expression was noted in both the exocrine and endocrine pancreas, but the islets of Langerhans exhibited more powerful reactions. The ductal apparatus of the submandibular gland and lymphocytes situated in pericolonic lymph nodes were also TASK-3 positive. Strong TASK-3 positivity could also be observed in malignant gastrointestinal tumours, with intense nuclear-perinuclear labelling of some of the tumour cells. The present findings suggest that TASK-3 channels may have roles in the gastrointestinal functions, including insular hormone secretion.
Collapse
Affiliation(s)
- Ilona Kovács
- Department of Pathology, HBM Kenézy Gyula County Infirmary, Bartók Béla u. 2-26, Debrecen, 4043, Hungary
| | | | | | | | | | | | | |
Collapse
|
17
|
Pál B, Pór A, Pocsai K, Szücs G, Rusznák Z. Voltage-gated and background K+ channel subunits expressed by the bushy cells of the rat cochlear nucleus. Hear Res 2005; 199:57-70. [PMID: 15574300 DOI: 10.1016/j.heares.2004.07.020] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/22/2004] [Accepted: 07/15/2004] [Indexed: 11/16/2022]
Abstract
Bushy cells of the ventral cochlear nucleus produce a single, short latency action potential at the beginning of long depolarisations. In the present work an immunochemical survey was performed to detect the presence of K+ channel subunits which may contribute to the specific membrane properties of the bushy cells. The immunocytochemical experiments conducted on enzymatically isolated bushy cells indicated positive immunolabelling for several subunits known to be responsible for the genesis of rapidly inactivating K+ currents. Bushy cells showed strong expression of Kv3.4, 4.2 and 4.3 subunits, with the lack of Kv1.4 specific immunoreaction. The Kv3.4-specific immunoreaction had a specific, patchy appearance. Bushy cells also expressed various members of the Kv1 subunit family, most notably Kv1.1, 1.2, 1.3 and 1.6. Weak positivity could be observed for Kv3.2 subunits. The positive immunolabelling for Kv3.4, Kv4.2 and Kv4.3 was confirmed in free-floating tissue slices. Voltage-clamp experiments performed on positively identified bushy cells in brain slices corroborated the presence and activity of Kv3.4 and Kv4.2/4.3 containing K+ channels. Bushy cell showed strong immunopositivity for TASK-1 channels too. The results presented in this work indicate that bushy cells possess several types of voltage-gated K+ channel subunits whose activity may contribute to the membrane properties and firing characteristics of these neurones.
Collapse
Affiliation(s)
- Balázs Pál
- Department of Physiology, Medical and Health Science Centre, University of Debrecen, P.O. Box 22, Debrecen, H-4012, Hungary
| | | | | | | | | |
Collapse
|
18
|
Rusznák Z, Pocsai K, Kovács I, Pór A, Pál B, Bíró T, Szücs G. Differential distribution of TASK-1, TASK-2 and TASK-3 immunoreactivities in the rat and human cerebellum. Cell Mol Life Sci 2004; 61:1532-42. [PMID: 15197476 DOI: 10.1007/s00018-004-4082-3] [Citation(s) in RCA: 27] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/26/2022]
Abstract
In this work, the distributions of some acid-sensitive two-pore-domain K+ channels (TASK-1, TASK-2 and TASK-3) were investigated in the rat and human cerebellum. Astrocytes situated in rat cerebellar tissue sections were positive for TASK-2 channels. Purkinje cells were strongly stained and granule cells and astrocytes were moderately positive for TASK-3. Astrocytes isolated from the hippocampus, cerebellum and cochlear nucleus expressed TASK channels in a primary tissue culture. Our results suggest that TASK channel expression may be significant in the endoplasmic reticulum of the astrocytes. The human cerebellum showed weak TASK-2 immunolabelling. The pia mater, astrocytes, Purkinje and granule cells demonstrated strong TASK-1 and TASK-3 positivities. The TASK-3 labelling was stronger in general, but it was particularly intense in the Purkinje cells and pia mater.
Collapse
Affiliation(s)
- Z Rusznák
- Department of Physiology, Medical and Health Science Centre, University of Debrecen, 4012 Debrecen, Hungary.
| | | | | | | | | | | | | |
Collapse
|