Distinct effects of orexin A on spontaneous and evoked synaptic currents in the rat nucleus tractus solitarius
Orexins are produced in hypothalamic areas and orexin-containing neurons are distributed in widespread areas of the central nervous system. Orexins regulate several physiological functions such as arousal, food intake and autonomic control. The presence of orexin-containing neuron terminals and orex...
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| Format: | Article |
| Language: | English |
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Elsevier
2022-12-01
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| Series: | Journal of Pharmacological Sciences |
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| Online Access: | http://www.sciencedirect.com/science/article/pii/S1347861322000755 |
| _version_ | 1828315792824860672 |
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| author | Yoshiaki Ohi Yuki Asai Daisuke Kodama |
| author_facet | Yoshiaki Ohi Yuki Asai Daisuke Kodama |
| author_sort | Yoshiaki Ohi |
| collection | DOAJ |
| description | Orexins are produced in hypothalamic areas and orexin-containing neurons are distributed in widespread areas of the central nervous system. Orexins regulate several physiological functions such as arousal, food intake and autonomic control. The presence of orexin-containing neuron terminals and orexin receptors has been confirmed in the nucleus tractus solitarius (NTS), which receives primary afferent fibers from peripheral organs including baroreceptors. However, the neuronal effects of orexin-1 receptor (OX1R) activation were not examined. Here, we aimed to determine the effects of OX1R activation on excitatory synaptic transmission. OX1R activation increased the frequency of spontaneous excitatory synaptic currents (sEPSCs). This effect was blocked by the prior application of L-NAME. In contrast, the amplitude of evoked excitatory postsynaptic currents (eEPSCs) was suppressed by OX1R activation, and this effect was prevented by a cannabinoid receptor 1 blocker, AM251, but not by the pretreatment with L-NAME. Altogether, these results suggest that OX1R activation increases sEPSCs frequency by stimulating NO production, whereas it inhibits eEPSCs by releasing endocannabinoids in the NTS. Thus, OX1R activation had distinct effects on spontaneous and evoked excitatory synaptic transmissions in the NTS. |
| first_indexed | 2024-04-13T17:05:08Z |
| format | Article |
| id | doaj.art-6aefb3023cd2408c8ec18ef194143269 |
| institution | Directory Open Access Journal |
| issn | 1347-8613 |
| language | English |
| last_indexed | 2024-04-13T17:05:08Z |
| publishDate | 2022-12-01 |
| publisher | Elsevier |
| record_format | Article |
| series | Journal of Pharmacological Sciences |
| spelling | doaj.art-6aefb3023cd2408c8ec18ef1941432692022-12-22T02:38:30ZengElsevierJournal of Pharmacological Sciences1347-86132022-12-011504244250Distinct effects of orexin A on spontaneous and evoked synaptic currents in the rat nucleus tractus solitariusYoshiaki Ohi0Yuki Asai1Daisuke Kodama2Corresponding author. Laboratory of Neuropharmacology, School of Pharmacy, Aichi Gakuin University 1-100 Kusumoto-cho, Chikusa-ku, Nagoya 464-8650, Japan. Fax: +81 52 757 6799.; Laboratory of Neuropharmacology, School of Pharmacy, Aichi Gakuin University, Nagoya, JapanLaboratory of Neuropharmacology, School of Pharmacy, Aichi Gakuin University, Nagoya, JapanLaboratory of Neuropharmacology, School of Pharmacy, Aichi Gakuin University, Nagoya, JapanOrexins are produced in hypothalamic areas and orexin-containing neurons are distributed in widespread areas of the central nervous system. Orexins regulate several physiological functions such as arousal, food intake and autonomic control. The presence of orexin-containing neuron terminals and orexin receptors has been confirmed in the nucleus tractus solitarius (NTS), which receives primary afferent fibers from peripheral organs including baroreceptors. However, the neuronal effects of orexin-1 receptor (OX1R) activation were not examined. Here, we aimed to determine the effects of OX1R activation on excitatory synaptic transmission. OX1R activation increased the frequency of spontaneous excitatory synaptic currents (sEPSCs). This effect was blocked by the prior application of L-NAME. In contrast, the amplitude of evoked excitatory postsynaptic currents (eEPSCs) was suppressed by OX1R activation, and this effect was prevented by a cannabinoid receptor 1 blocker, AM251, but not by the pretreatment with L-NAME. Altogether, these results suggest that OX1R activation increases sEPSCs frequency by stimulating NO production, whereas it inhibits eEPSCs by releasing endocannabinoids in the NTS. Thus, OX1R activation had distinct effects on spontaneous and evoked excitatory synaptic transmissions in the NTS.http://www.sciencedirect.com/science/article/pii/S1347861322000755OrexinOrexin-1 receptorNucleus tractus solitariusPatch-clamp recordingEndocannabinoid |
| spellingShingle | Yoshiaki Ohi Yuki Asai Daisuke Kodama Distinct effects of orexin A on spontaneous and evoked synaptic currents in the rat nucleus tractus solitarius Journal of Pharmacological Sciences Orexin Orexin-1 receptor Nucleus tractus solitarius Patch-clamp recording Endocannabinoid |
| title | Distinct effects of orexin A on spontaneous and evoked synaptic currents in the rat nucleus tractus solitarius |
| title_full | Distinct effects of orexin A on spontaneous and evoked synaptic currents in the rat nucleus tractus solitarius |
| title_fullStr | Distinct effects of orexin A on spontaneous and evoked synaptic currents in the rat nucleus tractus solitarius |
| title_full_unstemmed | Distinct effects of orexin A on spontaneous and evoked synaptic currents in the rat nucleus tractus solitarius |
| title_short | Distinct effects of orexin A on spontaneous and evoked synaptic currents in the rat nucleus tractus solitarius |
| title_sort | distinct effects of orexin a on spontaneous and evoked synaptic currents in the rat nucleus tractus solitarius |
| topic | Orexin Orexin-1 receptor Nucleus tractus solitarius Patch-clamp recording Endocannabinoid |
| url | http://www.sciencedirect.com/science/article/pii/S1347861322000755 |
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