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| Predicate | Object |
|---|---|
| rdf:type | |
| lifeskim:mentions | |
| pubmed:issue |
2
|
| pubmed:dateCreated |
1999-3-4
|
| pubmed:abstractText |
The petrosal ganglion supplies chemoafferent pathways via the glossopharyngeal (IXth) nerve to peripheral targets which release various neurotransmitters including serotonin (5-HT). Here, we combined rapid 5-HT application with patch clamp, whole-cell recording to investigate whether 5-HT receptors are expressed on isolated petrosal neurons (PN), cultured from 7-12 day-old rat pups. In responsive cells, the dominant effect of 5-HT was a rapid depolarization associated with a conductance increase in approximately 43% of the neurons (53/123); however, in a minority population ( approximately 6%; 8/123), 5-HT caused membrane depolarization associated with a conductance decrease. In the former group, 5-HT produced a transient inward current (I5-HT) in neurons voltage-clamped near the resting potential ( approximately -60 mV); the effect was mimicked by the 5-HT3 receptor-specific agonist, 2-methyl-5-HT, suggesting it was mediated by 5-HT3 receptors. Further, I5-HT was selectively inhibited by the 5-HT3 receptor-specific antagonist MDL72222 (1-10 microM), but was unaffected by either 5-HT1/5-HT2 receptor antagonist, spiperone, or by 5-HT2 receptor-specific antagonist, ketanserin (50-100 microM). I5-HT displayed moderate inward rectification and had a mean reversal potential (+/-S.E.M.) of -4.3+/-6.6 mV (n=6). Application of 5-HT (dose range: 0.1-100 microM) produced a dose-response curve that was fitted by the Hill equation with EC50= approximately 3.4 microM and Hill coefficient= approximately 1.6 (n=8). The activation phase of I5-HT (10 microM 5-HT at -60 mV) was well fitted by a single exponential with mean (+/-S.E.M.) time constant of 45+/-30 ms (n=6). The desensitization phase of I5-HT was best fitted by a single exponential with mean (+/-S.E.M.) time constant of 660+/-167 ms (n=6). Fluctuation analysis yielded an apparent mean single-channel conductance (+/-S.E.M) of 2.7+/-1.5 pS (n=4) at -60 mV. In the minority ( approximately 6%) population of neurons which responded to 5-HT with a conductance decrease, the depolarization was blocked by the 5-HT2 receptor antagonist, ketanserin (50 microM). Taken together, these results suggest that 5-HT3 receptors are the major subtype expressed by rat petrosal neurons, and therefore are candidates for facilitating chemoafferent excitation in response to 5-HT released from peripheral targets.
|
| pubmed:language |
eng
|
| pubmed:journal | |
| pubmed:citationSubset |
IM
|
| pubmed:chemical | |
| pubmed:status |
MEDLINE
|
| pubmed:month |
Jan
|
| pubmed:issn |
0006-8993
|
| pubmed:author | |
| pubmed:copyrightInfo |
Copyright 1999 Published by Elsevier Science B.V.
|
| pubmed:issnType |
Print
|
| pubmed:day |
23
|
| pubmed:volume |
816
|
| pubmed:owner |
NLM
|
| pubmed:authorsComplete |
Y
|
| pubmed:pagination |
544-53
|
| pubmed:dateRevised |
2006-11-15
|
| pubmed:meshHeading |
pubmed-meshheading:9878879-Animals,
pubmed-meshheading:9878879-Cells, Cultured,
pubmed-meshheading:9878879-Coculture Techniques,
pubmed-meshheading:9878879-Electric Conductivity,
pubmed-meshheading:9878879-Ganglia,
pubmed-meshheading:9878879-Kinetics,
pubmed-meshheading:9878879-Membrane Potentials,
pubmed-meshheading:9878879-Neurons, Afferent,
pubmed-meshheading:9878879-Patch-Clamp Techniques,
pubmed-meshheading:9878879-Rats,
pubmed-meshheading:9878879-Receptors, Serotonin
|
| pubmed:year |
1999
|
| pubmed:articleTitle |
Electrophysiological characterization of 5-HT receptors on rat petrosal neurons in dissociated cell culture.
|
| pubmed:affiliation |
Department of Biology, McMaster University, 1280 Main St. West, Hamilton, ON, Canada.
|
| pubmed:publicationType |
Journal Article,
Research Support, Non-U.S. Gov't
|