The role of defensins in the excitability of the peripheral vestibular system in the frog: Evidence for the presence of communication between the immune and nervous systems
| Autor: | I. V. Ryzhova, G N Andrianov, Nozdrachev Ad |
|---|---|
| Rok vydání: | 2007 |
| Předmět: |
Atropine
alpha-Defensins medicine.medical_specialty N-Methylaspartate Neuroimmunomodulation Narcotic Antagonists Rana temporaria Action Potentials Glutamic Acid Kainate receptor (+)-Naloxone AMPA receptor In Vitro Techniques Biology Neurotransmission Inhibitory postsynaptic potential Synaptic Transmission Cholinergic Antagonists Defensins chemistry.chemical_compound Internal medicine medicine Animals Humans Cycloleucine Receptors Cholinergic Neurons Afferent alpha-Amino-3-hydroxy-5-methyl-4-isoxazolepropionic Acid Inflammation Kainic Acid Dose-Response Relationship Drug Naloxone Glutamate receptor Acetylcholine Semicircular Canals Sensory Systems Endocrinology Receptors Glutamate chemistry Metabotropic glutamate receptor Immune System Receptors Opioid ACPD Rabbits Vestibule Labyrinth |
| Zdroj: | Hearing Research. 230:1-8 |
| ISSN: | 0378-5955 |
| DOI: | 10.1016/j.heares.2007.05.003 |
| Popis: | Defensins are one of the major groups of endogenous peptides that are considered to be important antibiotic-like effectors of host innate and adaptive antimicrobial immunity. The current study investigated the electrophysiological effects of externally applied human and rabbit defensins (HNP-1 and RNP-1, correspondingly) on afferent neurotransmission in the frog semicircular canals (SCC). Application of HNP-1 and RNP-1 induces a concentration-dependent decrease in resting activity. Threshold concentrations for both substances were of the order of 0.0001 nM. The firing evoked by L-glutamate (L-Glu) and its agonists alpha-amino-3-hydroxy-5-methylisoxazole-4-propionate (AMPA), kainate and N-methyl-D-aspartate (NMDA) and (1S, 3R)-1-aminocyclopentane-trans-1,3-dicarboxilic acid (ACPD) could be inhibited by HNP-1, suggesting that defensins exert inhibitory control over both ionotropic and metabotropic glutamate receptors. HNP-1 considerably inhibited the L-glutamate/high Mg2+ -induced increase in frequency, thus, demonstrating its postsynaptic site of action. Acetylcholine (ACh) responses under HNP-1 did not differ from the frequency increase induced by ACh alone, and the ACh antagonist atropine left the response to HNP-1 intact. The specific opioid receptor antagonist naloxone (Nal) antagonized the inhibitory response evoked by HNP-1. The results obtained support the evidence for the recruitment of defensins in communication between the immune and nervous systems, and on the potential of sensory receptors to participate in the inflammatory response. |
| Databáze: | OpenAIRE |
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