| 5-HT offsets homeostasis of synaptic transmission during short-term facilitation. | |
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MedLine Citation:
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PMID: 15033966 Owner: NLM Status: MEDLINE |
Abstract/OtherAbstract:
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In this study, we approach the topic of vesicle recruitment and recycling by perturbing neurotransmission at the crayfish neuromuscular junction with altered electrical activity and the presence of the neuromodulator serotonin (5-HT). After induction of short-term facilitation (STF) with stimulus pulse trains (40 Hz, 20 pulses), the amount of synaptic transmission can be maintained at a relatively constant level, producing a plateau in the amplitude of the excitatory postsynaptic potentials (EPSPs) throughout the remaining stimuli within a train of a few hundred milliseconds. With an increase in the frequency of the stimuli within a train (60 Hz, 20 pulses), an altered plateau of larger EPSP amplitudes occurs. This suggests that differential rates of vesicle recruitment can be rapidly reached and maintained. Exposure of nerve terminals to 5-HT further enhances the EPSP amplitudes to yet a higher plateau level. The effect of 5-HT is more pronounced for 40-Hz pulse trains than for 60-Hz trains. This suggests that 5-HT can recruit vesicles into the readily releasable pool (RRP) and that the recruitment is limited at higher stimulation frequencies. The attainment of a larger amplitude in the plateaus of the EPSPs at 60 Hz compared with 40 Hz also suggests that the rapid induction of STF enhances the entry of vesicles into the RRP. By direct quantal counts, mean quantal content increases linearly during STF, and 5-HT offsets the linear release. We propose that 5-HT and electrically induced recruitment of vesicles from a reserve pool to the RRP may share similar recruitment mechanisms. |
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Authors:
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G M Sparks; R L Cooper |
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Publication Detail:
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Type: In Vitro; Journal Article; Research Support, Non-U.S. Gov't; Research Support, U.S. Gov't, Non-P.H.S. Date: 2004-03-19 |
Journal Detail:
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Title: Journal of applied physiology (Bethesda, Md. : 1985) Volume: 96 ISSN: 8750-7587 ISO Abbreviation: J. Appl. Physiol. Publication Date: 2004 May |
Date Detail:
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Created Date: 2004-04-12 Completed Date: 2004-12-14 Revised Date: 2006-11-15 |
Medline Journal Info:
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Nlm Unique ID: 8502536 Medline TA: J Appl Physiol Country: United States |
Other Details:
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Languages: eng Pagination: 1681-90 Citation Subset: IM |
Affiliation:
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Department of Biology, University of Kentucky, Lexington, KY 40506-0225, USA. |
Export Citation:
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APA/MLA Format Download EndNote Download BibTex |
| MeSH Terms | |
Descriptor/Qualifier:
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Animals Astacoidea Electric Stimulation Excitatory Postsynaptic Potentials / drug effects Extremities / innervation* Homeostasis / drug effects* Serotonin / pharmacology* Synaptic Transmission / drug effects* |
| Chemical | |
Reg. No./Substance:
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50-67-9/Serotonin |
From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine
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