Nicotine inhibits firing activity of dorsal raphe 5-HT neurones in vivo.
It is established that the brain monoaminergic systems are among the main targets of several dependence-inducing drugs, including nicotine. In the present study extracellular electrophysiological recordings were performed to investigate the effects of nicotine on dorsal raphe 5-HT neurones. Nicotine...
| Main Authors: | , , , |
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| Format: | Journal article |
| Language: | English |
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2000
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| _version_ | 1826258535365738496 |
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| author | Engberg, G Erhardt, S Sharp, T Hajós, M |
| author_facet | Engberg, G Erhardt, S Sharp, T Hajós, M |
| author_sort | Engberg, G |
| collection | OXFORD |
| description | It is established that the brain monoaminergic systems are among the main targets of several dependence-inducing drugs, including nicotine. In the present study extracellular electrophysiological recordings were performed to investigate the effects of nicotine on dorsal raphe 5-HT neurones. Nicotine, administered systemically (50-400 microg/kg, i.v.) in chloral hydrate-anaesthetised rats, induced a transient inhibition of the majority of 5-HT neurones recorded (38 of 45). The inhibition was rapid in onset (about 30 s) and the firing rate returned to baseline within 1-3 min. No apparent tachyphylaxis was observed to this inhibitory effect. The centrally acting nicotine antagonist mecamylamine (4 mg/kg, i.v.), but not the peripherally acting nicotine antagonist chlorisondamine (0.3 mg/kg, i.v.) antagonised the nicotine-induced inhibition of 5-HT neurones. The inhibition of 5-HT neurones was also blocked with a selective 5-HT1A receptor antagonist (WAY 100635; 0.1 mg/kg, i.v.), indicating a possible involvement of somato-dendritic 5-HT1A receptors in the effect of nicotine. Interestingly, microiontophoretic application of nicotine into the dorsal raphe failed to inhibit 5-HT neurones, suggesting an indirect effect of nicotine on 5-HT neurones, possibly involving afferent pathways. |
| first_indexed | 2024-03-06T18:35:29Z |
| format | Journal article |
| id | oxford-uuid:0b11c90c-0148-47b7-bef1-a6a612a6ca7c |
| institution | University of Oxford |
| language | English |
| last_indexed | 2024-03-06T18:35:29Z |
| publishDate | 2000 |
| record_format | dspace |
| spelling | oxford-uuid:0b11c90c-0148-47b7-bef1-a6a612a6ca7c2022-03-26T09:27:32ZNicotine inhibits firing activity of dorsal raphe 5-HT neurones in vivo.Journal articlehttp://purl.org/coar/resource_type/c_dcae04bcuuid:0b11c90c-0148-47b7-bef1-a6a612a6ca7cEnglishSymplectic Elements at Oxford2000Engberg, GErhardt, SSharp, THajós, MIt is established that the brain monoaminergic systems are among the main targets of several dependence-inducing drugs, including nicotine. In the present study extracellular electrophysiological recordings were performed to investigate the effects of nicotine on dorsal raphe 5-HT neurones. Nicotine, administered systemically (50-400 microg/kg, i.v.) in chloral hydrate-anaesthetised rats, induced a transient inhibition of the majority of 5-HT neurones recorded (38 of 45). The inhibition was rapid in onset (about 30 s) and the firing rate returned to baseline within 1-3 min. No apparent tachyphylaxis was observed to this inhibitory effect. The centrally acting nicotine antagonist mecamylamine (4 mg/kg, i.v.), but not the peripherally acting nicotine antagonist chlorisondamine (0.3 mg/kg, i.v.) antagonised the nicotine-induced inhibition of 5-HT neurones. The inhibition of 5-HT neurones was also blocked with a selective 5-HT1A receptor antagonist (WAY 100635; 0.1 mg/kg, i.v.), indicating a possible involvement of somato-dendritic 5-HT1A receptors in the effect of nicotine. Interestingly, microiontophoretic application of nicotine into the dorsal raphe failed to inhibit 5-HT neurones, suggesting an indirect effect of nicotine on 5-HT neurones, possibly involving afferent pathways. |
| spellingShingle | Engberg, G Erhardt, S Sharp, T Hajós, M Nicotine inhibits firing activity of dorsal raphe 5-HT neurones in vivo. |
| title | Nicotine inhibits firing activity of dorsal raphe 5-HT neurones in vivo. |
| title_full | Nicotine inhibits firing activity of dorsal raphe 5-HT neurones in vivo. |
| title_fullStr | Nicotine inhibits firing activity of dorsal raphe 5-HT neurones in vivo. |
| title_full_unstemmed | Nicotine inhibits firing activity of dorsal raphe 5-HT neurones in vivo. |
| title_short | Nicotine inhibits firing activity of dorsal raphe 5-HT neurones in vivo. |
| title_sort | nicotine inhibits firing activity of dorsal raphe 5 ht neurones in vivo |
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