Modulation of Electrical Activity by 5-Hydroxytryptamine in Crayfish Neurosecretory Cells

作者：Francisco Sáenz, Ubaldo Garcı́a, Hugo Aréchigá · 发表于：Journal of Experimental Biology · 年份：1997 · DOI：10.1242/jeb.200.23.3079 · 被引用次数：35 · 研究领域：Neurobiology and Insect Physiology Research、Ion channel regulation and function、Neuroscience and Neuropharmacology Research

The effect of 5-hydroxytryptamine (5-HT) was tested in a population of X organ neurosecretory cells in the eyestalk of the crayfish Procambarus clarkii. Tests were conducted both in situ and on isolated neurones kept in culture. The application of 5-HT induced action potentials in silent cells. In spontaneously active neurones, 5-HT increased the firing rate and either induced firing or enhanced bursting activity. The effect of 5-HT was dose-dependent within the range 1-100 micromol l-1 in cells of the intact organ. The effect persisted for 20-30 min after 5-HT had been removed from the bathing solution. Successive applications of 5-HT onto the same neurone reduced responsiveness, suggesting that desensitization had occurred. The effects of 5-HT were blocked by prior incubation with the 5-HT antagonist methysergide. In X organ cells whose axons and branches in the neuropile had been severed, 5-HT induced a depolarisation associated with a slow inward current. In X organ neurones isolated from the eyestalk and kept in culture, 5-HT was capable of evoking bursts of action potentials and elicited a slow inward current. This effect was also blocked by methysergide (10(-4 )mol l-1). These results suggest a direct modulatory effect of 5-HT on the pattern of electrical activity in the X organ cells.