Abstract
Slow changes in [Ca(2+)](i) reflect increased neuronal activity. Our study demonstrates that single-trial fast [Ca(2+)](i) imaging (≥200 Hz sampling rate) revealed peaks each of which are associated with single spike discharge recorded by consecutive voltage-sensitive dye (VSD) imaging in enteric neurones and nerve fibres. Fast [Ca(2+)](i) imaging also revealed subthreshold fast excitatory postsynaptic potentials. Nicotine-evoked [Ca(2+)](i) peaks were reduced by -conotoxin and blocked by ruthenium red or tetrodotoxin. Fast [Ca(2+)](i) imaging can be used to directly record single action potentials in enteric neurones. [Ca(2+)](i) peaks required opening of voltage-gated sodium and calcium channels as well as Ca(2+) release from intracellular stores.
MeSH terms
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Action Potentials / physiology*
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Aniline Compounds / pharmacology
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Animals
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Calcium / physiology*
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Calcium Channel Blockers / pharmacology
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Excitatory Postsynaptic Potentials / physiology
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Fluorescent Dyes / pharmacology
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Guinea Pigs
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Humans
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Ileum / physiology
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Male
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Myenteric Plexus / physiology*
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Neurons / physiology*
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Nicotine / pharmacology
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Nicotinic Agonists / pharmacology
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Pyridinium Compounds / pharmacology
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Ruthenium Red / pharmacology
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Tetrodotoxin / pharmacology
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Voltage-Sensitive Dye Imaging
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Xanthenes / pharmacology
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omega-Conotoxins / pharmacology
Substances
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1-(3-sulfonatopropyl)-4-(beta-(2-(di-n-octylamino)-6-naphthyl)vinyl)pyridinium betaine
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Aniline Compounds
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Calcium Channel Blockers
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Fluo 4
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Fluorescent Dyes
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Nicotinic Agonists
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Pyridinium Compounds
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Xanthenes
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omega-Conotoxins
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Ruthenium Red
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Tetrodotoxin
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Nicotine
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Calcium