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Druzin, Michael
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Publications (10 of 22) Show all publications
Yelhekar, T. D., Druzin, M. & Johansson, S. (2017). Contribution of Resting Conductance, GABA(A)-Receptor Mediated Miniature Synaptic Currents and Neurosteroid to Chloride Homeostasis in Central Neurons. eNeuro, 4(2), Article ID e0019.
Open this publication in new window or tab >>Contribution of Resting Conductance, GABA(A)-Receptor Mediated Miniature Synaptic Currents and Neurosteroid to Chloride Homeostasis in Central Neurons
2017 (English)In: eNeuro, ISSN 2373-2822, Vol. 4, no 2, article id e0019Article in journal (Refereed) Published
Abstract [en]

Maintenance of a low intraneuronal Cl- concentration, [Cl-](i), is critical for inhibition in the CNS. Here, the contribution of passive, conductive Cl- flux to recovery of [Cl-](i) after a high load was analyzed in mature central neurons from rat. A novel method for quantifying the resting Cl- conductance, important for [Cl-](i) recovery, was developed and the possible contribution of GABAA and glycine receptors and of ClC-2 channels to this conductance was analyzed. The hypothesis that spontaneous, action potential-independent release of GABA is important for [Cl-](i) recovery was tested. [Cl-](i) was examined by gramicidin-perforated patch recordings in medial preoptic neurons. Cells were loaded with Cl- by combining GABA or glycine application with a depolarized voltage, and the time course of [Cl-](i) was followed by measurements of the Cl- equilibrium potential, as obtained from the current recorded during voltage ramps combined with GABA or glycine application. The results show that passive Cl- flux contributes significantly, in the same order of magnitude as does K+-Cl- cotransporter 2 (KCC2), to [Cl-](i) recovery and that Cl- conductance accounts for similar to 6% of the total resting conductance. A major fraction of this resting Cl- conductance is picrotoxin (PTX)-sensitive and likely due to open GABAA receptors, but ClC-2 channels do not contribute. The results also show that when the decay of GABAA receptor-mediated miniature postsynaptic currents (minis) is slowed by the neurosteroid allopregnanolone, such minis may significantly quicken [Cl-](i) recovery, suggesting a possible steroid-regulated role for minis in the control of Clhomeostasis.

Keywords
chloride homeostasis, GABA(A) receptor, KCC2, miniature postsynaptic current, neurosteroid, resting loride conductance
National Category
Physiology
Identifiers
urn:nbn:se:umu:diva-133788 (URN)10.1523/ENEURO.0019-17.2017 (DOI)000397567900003 ()
Note

Originally published in manuscript form

Available from: 2017-04-24 Created: 2017-04-24 Last updated: 2018-06-09Bibliographically approved
Zhuravleva, Z., Titova, N., Mukhina, I. & Druzin, M. (2017). Preoptic glycine receptors: possible mediators of neuron-glial interaction affecting social behavior in male rats. Paper presented at 13th European Meeting on Glial Cells in Health and Disease, JUL 08-11, 2017, Edinburgh, SCOTLAND. Glia, 65, E298-E299
Open this publication in new window or tab >>Preoptic glycine receptors: possible mediators of neuron-glial interaction affecting social behavior in male rats
2017 (English)In: Glia, ISSN 0894-1491, E-ISSN 1098-1136, Vol. 65, p. E298-E299Article in journal, Meeting abstract (Refereed) Published
Place, publisher, year, edition, pages
John Wiley & Sons, 2017
National Category
Neurosciences
Identifiers
urn:nbn:se:umu:diva-137388 (URN)000403071700462 ()
Conference
13th European Meeting on Glial Cells in Health and Disease, JUL 08-11, 2017, Edinburgh, SCOTLAND
Note

Special Issue.

Available from: 2017-07-05 Created: 2017-07-05 Last updated: 2018-06-09Bibliographically approved
Druzin, M. & Johansson, S. (2016). 2-aminoethyl diphenylborinate blocks GABAA-receptor-mediated currents in rat medial preoptic neurons. Opera Medica Et Physiologica, 2(1), 63-68
Open this publication in new window or tab >>2-aminoethyl diphenylborinate blocks GABAA-receptor-mediated currents in rat medial preoptic neurons
2016 (English)In: Opera Medica Et Physiologica, ISSN 2500-2295, Vol. 2, no 1, p. 63-68Article in journal (Refereed) Published
Abstract [en]

The effect of 2-aminoethyl diphenylborinate (2-APB), a commonly used drug to modulate inositol-1,4,5-triphosphate (IP3) receptors and transient receptor potential (TRP) channels, on GABAA receptor-mediatedcurrents was studied in neurons from the medial preoptic nucleus (MPN) of rat. 2-APB gradually and reversibly reducedthe currents evoked by GABA but had no effect on the currents evoked by glycine. The blocking effect was not mediatedby alterations in intracellular calcium concentration and showed a concentration dependence with half maximal effect at~50 μM 2-APB, for currents evoked by 100 μM, as well as by 1.0 mM GABA, suggesting that 2-APB is not competing withGABA for its binding site at the GABAA receptor. Thus, the present study describes a novel pharmacological property of2-APB as a non-competitive blocker of GABAA receptors and calls for caution in the interpretation of the results where2-APB is used to affect IP3 receptors or TRP channels.

Place, publisher, year, edition, pages
Nizhni Novgorod: Lobachevsky State University of Nizhny Novgorod, 2016
National Category
Physiology
Identifiers
urn:nbn:se:umu:diva-133366 (URN)20388/OMP2016.001.0021 (DOI)
Available from: 2017-04-07 Created: 2017-04-07 Last updated: 2019-04-29Bibliographically approved
Johansson, S., Yelhekar, T. D. & Druzin, M. (2016). Commentary: Chloride Regulation: a Dynamic Equilibrium Crucial for Synaptic Inhibition. Frontiers in Cellular Neuroscience, 10, Article ID 182.
Open this publication in new window or tab >>Commentary: Chloride Regulation: a Dynamic Equilibrium Crucial for Synaptic Inhibition
2016 (English)In: Frontiers in Cellular Neuroscience, ISSN 1662-5102, E-ISSN 1662-5102, Vol. 10, article id 182Article in journal, Editorial material (Refereed) Published
Keywords
Cl- channel, K+ Cl- cotransporter 2, conductance, membrane potential, synaptic inhibition, Cl concentration, equilibrium potential
National Category
Neurosciences Physiology
Identifiers
urn:nbn:se:umu:diva-127569 (URN)10.3389/fncel.2016.00182 (DOI)000379894400002 ()27487962 (PubMedID)
Available from: 2016-11-16 Created: 2016-11-16 Last updated: 2018-06-09Bibliographically approved
Yelhekar, T. D., Druzin, M., Karlsson, U., Blomqvist, E. & Johansson, S. (2016). How to Properly Measure a Current-Voltage Relation? -Interpolation vs. Ramp Methods Applied to Studies of GABA(A) Receptors. Frontiers in Cellular Neuroscience, 10, Article ID 10.
Open this publication in new window or tab >>How to Properly Measure a Current-Voltage Relation? -Interpolation vs. Ramp Methods Applied to Studies of GABA(A) Receptors
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2016 (English)In: Frontiers in Cellular Neuroscience, ISSN 1662-5102, E-ISSN 1662-5102, Vol. 10, article id 10Article in journal (Refereed) Published
Abstract [en]

The relation between current and voltage, I-V relation, is central to functional analysis of membrane ion channels. A commonly used method, since the introduction of the voltage-clamp technique, to establish the I-V relation depends on the interpolation of current amplitudes recorded at different steady voltages. By a theoretical computational approach as well as by experimental recordings from GABA(A) receptor mediated currents in mammalian central neurons, we here show that this interpolation method may give reversal potentials and conductances that do not reflect the properties of the channels studied under conditions when ion flux may give rise to concentration changes. Therefore, changes in ion concentrations may remain undetected and conclusions on changes in conductance, such as during desensitization, may be mistaken. In contrast, an alternative experimental approach, using rapid voltage ramps, enable I-V relations that much better reflect the properties of the studied ion channels.

Keywords
current-voltage relation, voltage clamp, reversal potential, conductance, concentration changes, interpolation, voltage ramp, ion channel
National Category
Physiology Neurosciences
Identifiers
urn:nbn:se:umu:diva-127570 (URN)10.3389/fncel.2016.00010 (DOI)000369141200001 ()26869882 (PubMedID)
Available from: 2016-11-16 Created: 2016-11-16 Last updated: 2018-06-09Bibliographically approved
Lebedeva, A., Zhuravleva, Z., Denisov, P., Urazov, M., Tovpuga, V., Volnova, A., . . . Druzin, M. (2016). Mechanism of hypothalamus glycine receptor involvement in regulation of sexual behavior. Paper presented at 25th Anniversary of the FEPS, 168th Anniversary of French Physiological Society, Paris (France), June 29th– July 1st 2016. Acta Physiologica, 217, 95-95
Open this publication in new window or tab >>Mechanism of hypothalamus glycine receptor involvement in regulation of sexual behavior
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2016 (English)In: Acta Physiologica, ISSN 1748-1708, E-ISSN 1748-1716, Vol. 217, p. 95-95Article in journal, Meeting abstract (Other academic) Published
National Category
Physiology
Identifiers
urn:nbn:se:umu:diva-124348 (URN)000379514000218 ()
Conference
25th Anniversary of the FEPS, 168th Anniversary of French Physiological Society, Paris (France), June 29th– July 1st 2016
Note

Supplement: 708.

Special Issue: Abstracts of the 25th Anniversary of the FEPS, 168th Anniversary of French Physiological Society, Paris (France), June 29th– July 1st 2016.

Meeting Abstract: PO.156

Available from: 2016-12-06 Created: 2016-08-04 Last updated: 2018-06-09Bibliographically approved
Druzin, M. (2015). Setting neuronal chloride gradient: a new role for extracellular matrix. Acta Physiologica, 215, 45-45
Open this publication in new window or tab >>Setting neuronal chloride gradient: a new role for extracellular matrix
2015 (English)In: Acta Physiologica, ISSN 1748-1708, E-ISSN 1748-1716, Vol. 215, p. 45-45Article in journal, Meeting abstract (Other academic) Published
National Category
Physiology
Identifiers
urn:nbn:se:umu:diva-113449 (URN)000364786400098 ()
Available from: 2015-12-18 Created: 2015-12-18 Last updated: 2018-06-07Bibliographically approved
Zhuravleva, Z. D., Lebedeva, A. V., Volnova, A. B., Mukhina, I. V. & Druzin, M. Y. (2015). The effect of glycine microinjections in the medial preoptic area of the hypothalamus on the sexual behavior of male rats. Neurochemical Journal, 9(2), 141-145
Open this publication in new window or tab >>The effect of glycine microinjections in the medial preoptic area of the hypothalamus on the sexual behavior of male rats
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2015 (English)In: Neurochemical Journal, ISSN 1819-7124, Vol. 9, no 2, p. 141-145Article in journal (Refereed) Published
Abstract [en]

The mechanisms that underlie the early loss of the male reproductive function are still unknown. Therefore, investigation of this problem is an important task. The medial preoptic nucleus takes part in the regulation of sexual behavior; however, the role of glycine transmission in this nucleus has not yet been studied. Our study focuses on these questions.

Keywords
medial preoptic nucleus, hypothalamus, glycine, sexual behavior
National Category
Neurology
Identifiers
urn:nbn:se:umu:diva-106515 (URN)10.1134/S1819712415020117 (DOI)000355704600008 ()
Available from: 2015-07-15 Created: 2015-07-14 Last updated: 2018-06-07Bibliographically approved
Chizhov, A. V., Malinina, E., Druzin, M., Graham, L. J. & Johansson, S. (2014). Firing clamp: a novel method for single-trial estimation of excitatory and inhibitory synaptic neuronal conductances.. Frontiers in cellular neuroscience, 8(86), 86
Open this publication in new window or tab >>Firing clamp: a novel method for single-trial estimation of excitatory and inhibitory synaptic neuronal conductances.
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2014 (English)In: Frontiers in cellular neuroscience, ISSN 1662-5102, Vol. 8, no 86, p. 86-Article in journal (Refereed) Published
Abstract [en]

Understanding non-stationary neuronal activity as seen in vivo requires estimation of both excitatory and inhibitory synaptic conductances from a single trial of recording. For this purpose, we propose a new intracellular recording method, called "firing clamp." Synaptic conductances are estimated from the characteristics of artificially evoked probe spikes, namely the spike amplitude and the mean subthreshold potential, which are sensitive to both excitatory and inhibitory synaptic input signals. The probe spikes, timed at a fixed rate, are evoked in the dynamic-clamp mode by injected meander-like current steps, with the step duration depending on neuronal membrane voltage. We test the method with perforated-patch recordings from isolated cells stimulated by external application or synaptic release of transmitter, and validate the method with simulations of a biophysically-detailed neuron model. The results are compared with the conductance estimates based on conventional current-clamp recordings.

Keywords
synaptic conductance estimation, dynamic clamp, firing-clamp
National Category
Physiology
Identifiers
urn:nbn:se:umu:diva-88025 (URN)10.3389/fncel.2014.00086 (DOI)000333416900001 ()24734000 (PubMedID)
Available from: 2014-04-22 Created: 2014-04-22 Last updated: 2018-06-08Bibliographically approved
Alrifaiy, A., Bitaraf, N., Druzin, M., Lindahl, O. & Ramser, K. (2013). Hypoxia on a chip: a novel approach for patch-clamp studies in a microfluidic system with full oxygen control. In: Mian Long (Ed.), World Congress on Medical Physics and Biomedical Engineering May 26-31, 2012, Beijing, China: . Paper presented at World Congress on Medical Physics and Biomedical Engineering, 26 May 2012 through 31 May 2012, Beijing (pp. 313-316). Springer Berlin/Heidelberg
Open this publication in new window or tab >>Hypoxia on a chip: a novel approach for patch-clamp studies in a microfluidic system with full oxygen control
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2013 (English)In: World Congress on Medical Physics and Biomedical Engineering May 26-31, 2012, Beijing, China / [ed] Mian Long, Springer Berlin/Heidelberg, 2013, p. 313-316Conference paper, Published paper (Refereed)
Abstract [en]

A new approach to perform patch-clamp experiments on living cells under controlled anoxic and normoxic conditions was developed and tested. To provide an optimal control over the oxygen content and the biochemical environment a patch-clamp recording micropipette was integrated within an oxygen tight poly-methyl methacrylate (PMMA) based microchip. The oxygen content within the microfluidic chamber surrounding patch-clamp micropipette was maintained at 0.5-1.5 % by a continuous flow of artificial extracellular solution purged with nitrogen. The nerve and glial cells acutely obtained from the male rat brain were trapped by the optical tweezers and steered towards the patch-clamp micropipette through the channels of the microchip in order to achieve a close contact between the pipette and the cellular membrane. The patch-clamp recordings revealed that optical tweezers did not affect the electrophysiological properties of the tested cells suggesting that optical trapping is a safe and non-traumatizing method to manipulate living cells in the microfluidic system. Thus, our approach of combining optical tweezers and a gas-tight microfluidic chamber may be applied in various electrophysiological investigations of single cells were optimal control of the experimental conditions and the sample in a closed environment are necessary.

Place, publisher, year, edition, pages
Springer Berlin/Heidelberg, 2013
Series
IFMBE Proceedings, ISSN 1680-0737 ; 39
Keywords
lab-on-a-chip, nerve cell, optical tweezers, Patch-clamp
National Category
Biomedical Laboratory Science/Technology
Identifiers
urn:nbn:se:umu:diva-83237 (URN)10.1007/978-3-642-29305-4_84 (DOI)978-3-642-29304-7 (ISBN)978-3-642-29305-4 (ISBN)
Conference
World Congress on Medical Physics and Biomedical Engineering, 26 May 2012 through 31 May 2012, Beijing
Available from: 2013-11-21 Created: 2013-11-21 Last updated: 2018-06-08Bibliographically approved
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