- 期刊
Inhibition of Locus Coeruleus Neurons by Serotonin at High Doses
並列摘要
Using brain slice and intracellular recording techniques, this study was conducted in the attempt to evaluate whether serotonin (5-HT) is able to directly influence neuronal activities of the locus coeruleus (LC). LC neurons in the brain slice preparation show spontaneous firing in the absence of synaptic input; neurons in this work had firing rates ranging from 0.18-3.6Hz (mean=1.18±0.26Hz). Concentrations of 5-HT from 30 to 300μM were used, which reversibly decreased the spontaneous firing rate in 30 Out of 36LC neurons tested. In testing those cells with more than one concentration, the effect was dose-dependent. For LC neurons which showed complete block of firing by 5-HT (300μM), the latency to block was found to be directly related to the firing rate. In addition to the inhibition of spontaneous firing, 5-HT (300μM) also caused a 0-5mV (mean=3.2mV, n=10) hyperpolarization associated with a 2.2-21% (mean=11.5%, n=10) decrease in input resistance. Lower concentrations of 5-HT (30-100μM) did not produce any significant change in membrane potential or input resistance in neurons of the LC. The 5-HT receptor antagonist methysergide (10μM) was tested in 6 cells. Methysergide antagonized the 5-HT-induced inhibition of firing, hyperpolarization and reduction in input resistance. We concluded that 5-HT has inhibitory actions at high doses when applied to LC neurons in the brain slice preparation. 5-HT's inhibitory effects on LC neurons appear to be mediated by 5-HT receptors since they are antagonized by methysergide.
延伸閱讀
- Tseng, Z. T. (2012). Mutual regulation of neuregulin-1 and serotonin system in neuronal cells and astrocytes [master's thesis, National Taiwan University]. Airiti Library. https://doi.org/10.6342/NTU.2012.01967
- Pan, J. T. (1991). Neuroendocrine Control of Prolactin Secretion: The Role of the Serotonergic System. The Chinese Journal of Physiology, 34(1), 45-64. https://www.airitilibrary.com/Article/Detail?DocID=03044920-199103-34-1-45-64-a
- Tai, M. H., Teo, K. L., & Pan, J. T. (1990). Serotonin-Stimulated Prolactin Secretion May Not Involve the Dopaminergic System. The Chinese Journal of Physiology, 33(4), 345-352. https://www.airitilibrary.com/Article/Detail?DocID=03044920-199012-33-4-345-352-a
- Tsai, H. C. (2019). Role of Inhibitory Interneurons in the Locus Coeruleus in Startle and Pre-pulse Inhibition Behavior in Mouse [master's thesis, National Taiwan University]. Airiti Library. https://doi.org/10.6342/NTU201903603
- Lee, H. J., Park, H. J., Starkweather, A., An, K., & Shim, I. (2016). Decreased Interleukin-4 Release from the Neurons of the Locus Coeruleus in Response to Immobilization Stress. Mediators of Inflammation, 2016(), 1084-1091-098. https://doi.org/10.1155/2016/3501905