6-cyano-7-nitroquinoxaline-2-3-dione and picrotoxinin

Bone marrow mesenchymal stem cells (BMSCs) have been shown to be a promising cell type for the study of neuronal differentiation; however, few attempts had been made to differentiate these cells into inhibitory gamma-aminobutyric acid (GABA)ergic neurons. In this study, we over-expressed mammalian achaete-scute homologue-1 (Mash1), a basic helix-loop-helix (bHLH) transcription factor, in Sprague-Dawley rat BMSCs via lentiviral vectors, and then induced neuronal differentiation of these cells using conditioned medium. Our Western blot results show that, under conditions of differentiation, Mash1-overexpressing BMSCs exhibit an increased expression of neuronal markers and a greater degree of neuronal morphology compared to control, non-Mash1-overexpressing cells. Using immunocytochemistry, we observed increased expression of glutamic acid decarboxylase 67 (GAD67), as well as neuron-specific nuclear protein (NeuN) and β3-tubulin, in Mash1-overexpressing BMSCs compared to control cells. Moreover, we also found the differentiated cells showed representative traces of action potentials in electrophysiological characterization. In conclusion, our study demonstrated that over-expression of Mash1 can improve GABAergic differentiation of BMSCs in vitro.

Topics: 6-Cyano-7-nitroquinoxaline-2,3-dione; Animals; Basic Helix-Loop-Helix Transcription Factors; Cell Count; Cell Differentiation; Cells, Cultured; Excitatory Amino Acid Antagonists; GABA-A Receptor Antagonists; GABAergic Neurons; Glutamate Decarboxylase; Male; Membrane Potentials; Mesenchymal Stem Cells; Neurons; Phosphopyruvate Hydratase; Picrotoxin; Rats; Rats, Sprague-Dawley; Sesterterpenes; Valine

In this study on guinea pig hippocampal slices, protein kinase C (PKC) involvement in long-term potentiation (LTP) of GABAA and GABAB receptor-mediated fast and slow IPSPs, respectively, was examined. Stimulation of the stratum radiatum induced EPSPs followed by fast and slow IPSPs in the CA1 neurons. Tetanic stimulation of the stratum caused a marginal LTP of the fast IPSP but not of the slow IPSP. When K-252b, a potent inhibitor of PKC, was injected into CA1 neurons, LTP of fast and slow IPSPs was observed. These results indicate that PKC activation in CA1 neurons is involved in minimizing, rather than inducing, LTP of the IPSPs so that the EPSP is not distorted.

Topics: 6-Cyano-7-nitroquinoxaline-2,3-dione; Acetates; Acetic Acid; Animals; Baclofen; Carbazoles; Evoked Potentials; Guinea Pigs; Hippocampus; In Vitro Techniques; Indole Alkaloids; Neurons; Picrotoxin; Potentiometry; Protein Kinase C; Pyramidal Tracts; Quinoxalines; Sesterterpenes

In guinea pig hippocampal slices, a tetanic stimulation of the stratum radiatum caused long-term potentiation (LTP) of the excitatory postsynaptic potential (EPSP) but not of the GABAB receptor-mediated slow inhibitory postsynaptic potential (IPSP) in the CA1 neurons. In neurons in which Ca2+ was chelated with 1,2-bis(2-aminophenoxy) ethane N,N,N',N'-tetra-acetic acid (BAPTA) or ethylene-bis(oxyethylenenitrilo)tetra-acetic acid (EGTA), tetanic stimulation of the stratum radiatum caused LTP of the slow IPSP but not of the EPSP. These results indicate that a reciprocal relationship exists between LTP of the EPSP and LTP of the slow IPSP as far as the involvement of the postsynaptic Ca2+ is concerned.

Topics: 2-Amino-5-phosphonovalerate; 6-Cyano-7-nitroquinoxaline-2,3-dione; Animals; Calcium; Egtazic Acid; Guinea Pigs; Hippocampus; Membrane Potentials; Memory; Picrotoxin; Quinoxalines; Receptors, GABA-A; Sesterterpenes