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Detection of local serotonin release and clearance in the human small intestine using amperometry
Author(s) -
France Marion,
Galligan James,
Swain Greg
Publication year - 2013
Publication title -
the faseb journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.709
H-Index - 277
eISSN - 1530-6860
pISSN - 0892-6638
DOI - 10.1096/fasebj.27.1_supplement.1157.7
Subject(s) - enterochromaffin cell , serotonin transporter , serotonin , small intestine , chemistry , fluoxetine , motility , biophysics , 5 ht receptor , electrode , endocrinology , medicine , receptor , biology , microbiology and biotechnology , biochemistry
Serotonin (5‐hydroxytryptamine, 5‐HT) is an important signaling molecule in the gastrointestinal tract where it regulates motility and sensation. Alterations in 5‐HT signaling lead to impaired motility and visceral sensation. 5‐HT released from enterochromaffin (EC) cells residing in the mucosa acts at nearby intrinsic and extrinsic primary afferent neurons and its actions are terminated by uptake by the serotonin re‐uptake transporter (SERT). Continuous amperometry (CA) is used to investigate 5‐HT signaling mechanisms in real time near the mucosal surface (i.e. near sites of release and uptake). In CA, a potential applied to a working electrode will oxidize 5‐HT molecules arriving at the electrode surface at a mass transport limited rate producing a current. A current approach in which the electrode distance in relation to the mucosal surface decreases in a step‐wise fashion, can give information on 5‐HT uptake and release by the slope −1 and intercept slope −1 ratio, respectively, derived from a linear fit of a ln(current) vs. electrode distance plot. Uptake blocked by fluoxetine is indicated by an increase in the slope −1 . Measurements have been made in human small intestine obtained from patients undergoing bariatric surgery. Fluoxetine (1 μM) increased the slope −1 in preparations. Preliminary results suggest that this current approach is suitable for measurements in human small intestine and fluoxetine can be used to study SERT function.