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Ahtiainen A, Annala I, Rosenholm M, Kohtala S, Hyttinen J, Tanskanen JMA, Rantamäki T. Ketamine reduces electrophysiological network activity in cortical neuron cultures already at sub-micromolar concentrations - Impact on TrkB-ERK1/2 signaling. Neuropharmacology 2023; 229:109481. [PMID: 36868403 DOI: 10.1016/j.neuropharm.2023.109481] [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] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/05/2023] [Revised: 02/24/2023] [Accepted: 02/26/2023] [Indexed: 03/05/2023]
Abstract
The dissociative anesthetic ketamine regulates cortical activity in a dose-dependent manner. Subanesthetic-dose ketamine has paradoxical excitatory effects which is proposed to facilitate brain-derived neurotrophic factor (BDNF) (a ligand of tropomyosin receptor kinase B, TrkB) signaling, and activation of extracellular signal-regulated kinase 1/2 (ERK1/2). Previous data suggests that ketamine, at sub-micromolar concentrations, induces glutamatergic activity, BDNF release, and activation of ERK1/2 also on primary cortical neurons. We combined western blot analysis with multiwell-microelectrode array (mw-MEA) measurements to examine ketamine's concentration-dependent effects on network-level electrophysiological responses and TrkB-ERK1/2 phosphorylation in rat cortical cultures at 14 days in vitro. Ketamine did not cause an increase in neuronal network activity at sub-micromolar concentrations, but instead a decrease in spiking that was evident already at 500 nM concentration. TrkB phosphorylation was unaffected by the low concentrations, although BDNF elicited prominent phosphorylation response. High concentration of ketamine (10 μM) strongly reduced spiking, bursting and burst duration, which was accompanied with decreased phosphorylation of ERK1/2 but not TrkB. Notably, robust increases in spiking and bursting activity could be produced with carbachol, while it did not affect phosphorylation of TrkB or ERK1/2. Diazepam abolished neuronal activity, which was accompanied by reduced ERK1/2 phosphorylation without change on TrkB. In conclusion, sub-micromolar ketamine concentrations did not cause an increase in neuronal network activity or TrkB-ERK1/2 phosphorylation in cortical neuron cultures that readily respond to exogenously applied BDNF. Instead, pharmacological inhibition of network activity can be readily observed with high concentration of ketamine and it is associated with reduced ERK1/2 phosphorylation.
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Affiliation(s)
- A Ahtiainen
- Computational Biophysics and Imaging Group, BioMediTech, Faculty of Medicine and Health Technology, Tampere University, Arvo Ylpön katu 34, 33520, Tampere, Finland.
| | - I Annala
- Laboratory of Neurotherapeutics, Drug Research Program, Division of Pharmacology and Pharmacotherapy, Faculty of Pharmacy, University of Helsinki, Viikinkaari 5E, Biocenter 2, 00790, Helsinki, Finland; SleepWell Research Program, Faculty of Medicine, University of Helsinki, P.O. Box 9, Helsinki, 00014, Finland.
| | - M Rosenholm
- Laboratory of Neurotherapeutics, Drug Research Program, Division of Pharmacology and Pharmacotherapy, Faculty of Pharmacy, University of Helsinki, Viikinkaari 5E, Biocenter 2, 00790, Helsinki, Finland; Center for Translational Neuromedicine, Faculty of Health and Medical Sciences, University of Copenhagen, Blegdamsvej 3B, 2200, Copenhagen N, Denmark
| | - S Kohtala
- Laboratory of Neurotherapeutics, Drug Research Program, Division of Pharmacology and Pharmacotherapy, Faculty of Pharmacy, University of Helsinki, Viikinkaari 5E, Biocenter 2, 00790, Helsinki, Finland; SleepWell Research Program, Faculty of Medicine, University of Helsinki, P.O. Box 9, Helsinki, 00014, Finland; Department of Psychiatry, Feil Family Brain and Mind Research Institute, Weill Cornell Medicine, 407 E 61st St, New York, NY, 10065, USA
| | - J Hyttinen
- Computational Biophysics and Imaging Group, BioMediTech, Faculty of Medicine and Health Technology, Tampere University, Arvo Ylpön katu 34, 33520, Tampere, Finland
| | - J M A Tanskanen
- Computational Biophysics and Imaging Group, BioMediTech, Faculty of Medicine and Health Technology, Tampere University, Arvo Ylpön katu 34, 33520, Tampere, Finland
| | - T Rantamäki
- Laboratory of Neurotherapeutics, Drug Research Program, Division of Pharmacology and Pharmacotherapy, Faculty of Pharmacy, University of Helsinki, Viikinkaari 5E, Biocenter 2, 00790, Helsinki, Finland; SleepWell Research Program, Faculty of Medicine, University of Helsinki, P.O. Box 9, Helsinki, 00014, Finland
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Yan Y, Eipper BA, Mains RE. Kalirin is required for BDNF-TrkB stimulated neurite outgrowth and branching. Neuropharmacology 2016; 107:227-38. [PMID: 27036892 DOI: 10.1016/j.neuropharm.2016.03.050] [Citation(s) in RCA: 26] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/29/2015] [Revised: 03/03/2016] [Accepted: 03/28/2016] [Indexed: 01/19/2023]
Abstract
Exogenous brain-derived neurotrophic factor (BDNF), acting through TrkB, is known to promote neurite formation and branching. This response to BDNF was eliminated by inhibition of TrkB kinase and by specific inhibition of the GEF1 domain of Kalirin, which activates Rac1. Neurons from Kalrn knockout mice were unable to activate Rac1 in response to BDNF. BDNF-triggered neurite outgrowth was abolished when Kalrn expression was reduced using shRNA that targets all of the major Kalrn isoforms, and reduced in neurons from Kalrn knockout mice. The Kalrn isoforms expressed early in development also include a GEF2 domain that activates RhoA. However, BDNF-stimulated neurite outgrowth in Kalrn knockout neurons was rescued by expression of Kalirin-7, which includes only the GEF1 domain but lacks the GEF2 domain. Dendritic morphogenesis, which requires spatially restricted, coordinated changes in the actin cytoskeleton and in the organization of microtubules, involves essential contributions from multiple Rho GEFs. Since Tiam1, another Rho GEF, is also required for BDNF-stimulated neurite outgrowth, an inhibitory fragment of Tiam1 (PHn-CC-EX) was tested and found to interfere with both Kalirin and Tiam1 GEF activity. The prolonged TrkB activation observed in response to BDNF in Kalrn knockout neurons and the altered time course and extent of ERK, CREB and Akt activation observed in the absence of Kalrn would be expected to alter the response of these neurons to other regulatory factors.
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Antila H, Autio H, Turunen L, Harju K, Tammela P, Wennerberg K, Yli-Kauhaluoma J, Huttunen HJ, Castrén E, Rantamäki T. Utilization of in situ ELISA method for examining Trk receptor phosphorylation in cultured cells. J Neurosci Methods 2013; 222:142-6. [PMID: 24239780 DOI: 10.1016/j.jneumeth.2013.11.001] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/03/2013] [Revised: 10/31/2013] [Accepted: 11/02/2013] [Indexed: 01/18/2023]
Abstract
BACKGROUND Trk receptor tyrosine kinases regulate multiple important neuronal processes during the development and in the adulthood. Tyrosine phosphorylation of Trk serves as the initial step in the Trk signaling pathway and indicates receptor' autocatalytic activity. However, methods allowing simple and large-scale Trk phosphorylation analyses in cultured cells are lacking. NEW METHOD We describe an in situ phospho-Trk ELISA (enzyme-linked immunosorbent assay) method where cell culture, receptor stimulation and Trk phosphorylation analysis are all performed on the same multiwell plate. RESULTS In situ phospho-Trk ELISA readily and specifically detects neurotrophin-induced Trk phosphorylation in cultured cells. A proof-of-concept small molecule screening of a library composed of 2000 approved drugs and other bioactive compounds was carried out using this novel method. COMPARISON WITH EXISTING METHODS In situ phospho-Trk ELISA utilizes the principles and advantages of conventional sandwich ELISA in an in situ context. CONCLUSIONS We describe a novel method that can be efficiently used to examine Trk receptor phosphorylation in cultured cells. Principally similar methods can be developed to examine the levels and signaling of any intracellular protein.
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Affiliation(s)
- Hanna Antila
- Neuroscience Center, P.O. Box 56, Viikinkaari 4, FI-00014 University of Helsinki, Finland
| | - Henri Autio
- Neuroscience Center, P.O. Box 56, Viikinkaari 4, FI-00014 University of Helsinki, Finland
| | - Laura Turunen
- Institute For Molecular Medicine Finland (FIMM), P.O. Box 20, Tukholmankatu 8, FI-00014 University of Helsinki, Finland
| | - Kirsi Harju
- Division of Pharmaceutical Chemistry, Faculty of Pharmacy, P.O. Box 56, Viikinkaari 5 E, FI-00014 University of Helsinki, Finland
| | - Päivi Tammela
- Centre for Drug Research, Faculty of Pharmacy, P.O. Box 56, Viikinkaari 5 E, FI-00014 University of Helsinki, Finland
| | - Krister Wennerberg
- Institute For Molecular Medicine Finland (FIMM), P.O. Box 20, Tukholmankatu 8, FI-00014 University of Helsinki, Finland
| | - Jari Yli-Kauhaluoma
- Division of Pharmaceutical Chemistry, Faculty of Pharmacy, P.O. Box 56, Viikinkaari 5 E, FI-00014 University of Helsinki, Finland
| | - Henri J Huttunen
- Neuroscience Center, P.O. Box 56, Viikinkaari 4, FI-00014 University of Helsinki, Finland; Hermo Pharma Ltd., Viikinkaari 4, FI-00790 Helsinki, Finland
| | - Eero Castrén
- Neuroscience Center, P.O. Box 56, Viikinkaari 4, FI-00014 University of Helsinki, Finland
| | - Tomi Rantamäki
- Neuroscience Center, P.O. Box 56, Viikinkaari 4, FI-00014 University of Helsinki, Finland.
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