5-HT activates vagal afferent cell bodies in vivo: role of 5-HT2 and 5-HT3 receptors

P Lacolley; J R Owen; K Sandock; T H J Lewis; J N Bates; T P Robertson; S J Lewis

doi:10.1016/j.neuroscience.2006.07.032

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5-HT activates vagal afferent cell bodies in vivo: role of 5-HT2 and 5-HT3 receptors

Journal article

Peer reviewed

5-HT activates vagal afferent cell bodies in vivo: role of 5-HT2 and 5-HT3 receptors

P Lacolley, J R Owen, K Sandock, T H J Lewis, J N Bates, T P Robertson and S J Lewis

Neuroscience, Vol.143(1), pp.273-287

11/17/2006

DOI: 10.1016/j.neuroscience.2006.07.032

PMID: 17029799

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Abstract

Occipital artery (OA) injections of 5-HT elicit pronounced reductions in heart rate and mean arterial blood pressure (MAP) in urethane-anesthetized rats by activation of vagal afferent cell bodies in the ipsilateral nodose ganglion. In contrast, internal carotid artery (ICA) and i.v. injections elicit similar cardiovascular responses by activation of peripheral vagal afferent terminals. The aim of this study was to examine the roles of 5-HT3 and 5-HT2 receptors in the 5-HT-induced activation of vagal afferent cell bodies and peripheral afferent terminals in urethane-anesthetized rats. OA, ICA and i.v. injections of 5-HT elicited dose-dependent reductions in heart rate and MAP that were virtually abolished after i.v. administration of the 5-HT3 receptor antagonists, MDL 7222 or ICS 205-930. The responses elicited by the OA injections of 5-HT were markedly diminished after i.v. injection of the 5-HT2 receptor antagonists, xylamidine or ketanserin, whereas the responses elicited by i.v. or ICA injections of 5-HT were not affected. The present findings suggest that (1) 5-HT3 and 5-HT2 receptor antagonists gain ready access to nodose ganglion cells upon i.v. administration, and (2) functional 5-HT3 and 5-HT2 receptors exist on the cell bodies of vagal afferent neurons mediating the cardiovascular responses elicited by OA injections of 5-HT. These findings also support a wealth of evidence that 5-HT3 receptors exist on the peripheral terminals of vagal afferents, and although they do not discount the possibility that 5-HT2 receptors exist on peripheral vagal afferent terminals, it appears that activation of these receptors does not have pronounced effects on 5-HT3 receptor activity on terminals that mediate the hemodynamic responses to 5-HT.

Neurons, Afferent - drug effects

Drug Administration Routes

Rats

Male

Serotonin - pharmacology

Serotonin Antagonists - pharmacology

Rats, Sprague-Dawley

Vagus Nerve - cytology

Serotonin Receptor Agonists - pharmacology

Dose-Response Relationship, Drug

Heart Rate - drug effects

Muscarinic Antagonists - administration & dosage

Animals

Drug Interactions

Analysis of Variance

Receptors, Serotonin, 5-HT3 - physiology

Receptors, Serotonin, 5-HT2 - physiology

Blood Pressure - drug effects

Atropine - administration & dosage

Details

Title: Subtitle: 5-HT activates vagal afferent cell bodies in vivo: role of 5-HT2 and 5-HT3 receptors
Creators: P Lacolley - Department of Pharmacology, University of Iowa, Iowa City, IA 55242, USA. Patrick.Lacolley@nancy.inserm.fr
J R Owen
K Sandock
T H J Lewis
J N Bates
T P Robertson
S J Lewis
Resource Type: Journal article
Publication Details: Neuroscience, Vol.143(1), pp.273-287
Publisher: United States
DOI: 10.1016/j.neuroscience.2006.07.032
PMID: 17029799
ISSN: 0306-4522
eISSN: 1873-7544
Language: English
Date published: 11/17/2006
Academic Unit: Anesthesia
Record Identifier: 9984007294402771

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