Opioid peptides as possible neuromodulators of the afferent synaptic transmission in the frog semicircular canal
| Autor: | G. N. Andrianov, I.V Ryzhova |
|---|---|
| Rok vydání: | 1999 |
| Předmět: |
medicine.medical_specialty
Narcotic Antagonists Rana temporaria Glutamic Acid (+)-Naloxone In Vitro Techniques Neurotransmission Biology Pharmacology Synaptic Transmission chemistry.chemical_compound Nerve Fibers Postsynaptic potential Internal medicine medicine Animals Neurons Afferent Opioid peptide Neurotransmitter Neurotransmitter Agents Naloxone General Neuroscience Glutamate receptor Enkephalin Leucine-2-Alanine Vestibular nerve Semicircular Canals Endocrinology Opioid Peptides chemistry Receptors Opioid Excitatory postsynaptic potential |
| Zdroj: | Neuroscience. 93:801-806 |
| ISSN: | 0306-4522 |
| DOI: | 10.1016/s0306-4522(99)00159-1 |
| Popis: | Vestibular receptors of the frog, Rana temporaria , were examined for the effect of bath-applied opioid peptide leu-enkephalin, its synthetic analogue dalargin and the specific opiate antagonist naloxone. Multiunit afferent activity of the whole vestibular nerve was recorded in an in vitro preparation. Leu-enkephalin (0.005–100 nM) and dalargin (0.1–100 nM) depress the resting discharge frequency. Naloxone (10 nM–1 μM) antagonizes responses induced by leu-enkephalin and dalargin that suggests a specific action of opioid peptides. Leu-enkephalin and delargin inhibit the excitatory action of l -glutamate. The effects of opioid peptides on l -glutamate-induced responses are unaffected by Co 2+ block of transmitter release from hair cells that could speak in favour of the postsynaptic nature of these responses. At the same time, the other possible site of action of opioid peptides, such as efferent system, can not be excluded. The results indicate that opiate receptors are present in hair cells and that the neurotransmitter l -glutamate is involved in opiate action at the peripheral vestibular system of the frog. We suggest that opioid peptides may act as a neuromodulator in this system. |
| Databáze: | OpenAIRE |
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