1. Induction of long-term potentiation and long-term depression is cell-type specific in the spinal cord
- Author
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Jaebeom Jun, Jigong Wang, Hee Young Kim, Jin Mo Chung, Alice Bittar, and Kyungsoon Chung
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Patch-Clamp Techniques ,Green Fluorescent Proteins ,Long-Term Potentiation ,Biophysics ,Mice, Transgenic ,Biology ,Neuropathic pain ,Inhibitory postsynaptic potential ,NMDA receptors ,Synaptic plasticity ,Mice ,03 medical and health sciences ,0302 clinical medicine ,medicine ,Animals ,skin and connective tissue diseases ,Long-term depression ,Long-Term Synaptic Depression ,gamma-Aminobutyric Acid ,030304 developmental biology ,Neurons ,0303 health sciences ,Glutamate Decarboxylase ,GABA neurons ,Valine ,Long-term potentiation ,Carbocyanines ,Spinal cord ,Electric Stimulation ,Anesthesiology and Pain Medicine ,medicine.anatomical_structure ,Spinal Cord ,nervous system ,Neurology ,Spinothalamic tract neurons ,Excitatory postsynaptic potential ,NMDA receptor ,Calcium ,sense organs ,Neurology (clinical) ,Nerve Net ,Excitatory Amino Acid Antagonists ,Neuroscience ,030217 neurology & neurosurgery ,Research Paper - Abstract
This study shows that the direction of synaptic plastic changes in the spinal cord is cell-type specific in response to nociceptive input., The underlying mechanism of chronic pain is believed to be changes in excitability in spinal dorsal horn (DH) neurons that respond abnormally to peripheral input. Increased excitability in pain transmission neurons, and depression of inhibitory neurons, are widely recognized in the spinal cord of animal models of chronic pain. The possible occurrence of 2 parallel but opposing forms of synaptic plasticity, long-term potentiation (LTP) and long-term depression (LTD) was tested in 2 types of identified DH neurons using whole-cell patch-clamp recordings in mouse spinal cord slices. The test stimulus was applied to the sensory fibers to evoke excitatory postsynaptic currents in identified spinothalamic tract neurons (STTn) and GABAergic neurons (GABAn). Afferent conditioning stimulation (ACS) applied to primary afferent fibers with various stimulation parameters induced LTP in STTn but LTD in GABAn, regardless of stimulation parameters. These opposite responses were further confirmed by simultaneous dual patch-clamp recordings of STTn and GABAn from a single spinal cord slice. Both the LTP in STTn and the LTD in GABAn were blocked by an NMDA receptor antagonist, AP5, or an intracellular Ca2+ chelator, BAPTA. Both the pattern and magnitude of intracellular Ca2+ after ACS were almost identical between STTn and GABAn based on live-cell calcium imaging. The results suggest that the intense sensory input induces an NMDA receptor-dependent intracellular Ca2+ increase in both STTn and GABAn, but produces opposing synaptic plasticity. This study shows that there is cell type–specific synaptic plasticity in the spinal DH. more...
- Published
- 2015
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