Functional glutamatergic and glycinergic inputs to several superior olivary nuclei of the rat revealed by optical imaging
| Autor: | G. Srinivasan, Eckhard Friauf, Stefan Löhrke |
|---|---|
| Rok vydání: | 2004 |
| Předmět: |
Male
Optics and Photonics Auditory Pathways Glycine Glutamic Acid Kainate receptor In Vitro Techniques Olivary Nucleus Inhibitory postsynaptic potential Synaptic Transmission Functional Laterality Membrane Potentials Styrenes Rats Sprague-Dawley chemistry.chemical_compound Glutamatergic Postsynaptic potential Pons Animals Receptors AMPA Fluorescent Dyes Neurons General Neuroscience Neural Inhibition Strychnine Rats Electrophysiology Animals Newborn chemistry Superior olivary complex Synapses CNQX Excitatory postsynaptic potential Female Brainstem Excitatory Amino Acid Antagonists Neuroscience |
| Zdroj: | Neuroscience. 128:617-634 |
| ISSN: | 0306-4522 |
| DOI: | 10.1016/j.neuroscience.2004.06.012 |
| Popis: | Superior olivary complex (SOC) neurons receive excitatory and inhibitory inputs from both ears. We determined the nature of such inputs to the main SOC nuclei with an optical imaging system. To do so, brainstem slices of postnatal (P) rats (P3–13) were treated with the fast voltage-sensitive dye RH795, and ipsilateral and contralateral SOC inputs were activated electrically. Optical signals, equivalent to membrane potential changes, were detected by a 464-photodiode array. The signals consisted mostly of two components which were identified as pre- and postsynaptic potentials in experiments with Ca 2+ -free solutions. They correlated with morphological structures, i.e. the presynaptic components were prominent in neuropil regions whereas the postsynaptic components dominated in somata regions. Postsynaptic components were distinguished pharmacologically with the glycine receptor blocker strychnine and the α-amino-3-hydroxy-5-methyl-4-isoxazolepropionate (AMPA)/kainate receptor blocker 6-cyano-7-nitroquinoxaline-2,3-dione (CNQX). Concerning the lateral superior olive, we confirmed the known glutamatergic inputs from the ipsilateral side and the glycinergic inputs from the ipsilateral and contralateral sides. Furthermore, we identified a CNQX-sensitive input from the contralateral side. In the medial superior olive, we corroborated the glutamatergic and glycinergic inputs from the ipsilateral and contralateral sides. Both ipsi- and contralaterally, the glutamatergic input was more pronounced than the glycinergic input. In the superior paraolivary nucleus, we also identified ipsilateral and contralateral inputs. Besides the known glycinergic input from the contralateral side, we found a novel glycinergic input from the ipsilateral side and identified CNQX-sensitive inputs from the contralateral and ipsilateral sides. The latter was very weak and appeared only in 30% of the experiments. The data show the feasibility of identifying functional inputs to the SOC with voltage-sensitive dye recordings. |
| Databáze: | OpenAIRE |
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