Journal article
Tachyphylaxis to 5-HT3-receptor-mediated activation of vagal afferents is prevented by co-activation of 5-HT2 receptors
Brain research, Vol.1093(1), pp.105-115
2006
DOI: 10.1016/j.brainres.2006.03.090
PMID: 16712808
Abstract
Functional studies have provided evidence that 5-HT3 ion-channel receptors (5-HT3Rs) on vagal cardiopulmonary afferents mediating the Bezold-Jarisch reflex (BJR) rapidly desensitize upon repeated exposure to selective 5-HT3R agonists. G-protein-coupled 5-HT2 receptors (5-HT2Rs) also exist on vagal afferents, although activation of these receptors does not elicit the BJR. However, there is in vivo evidence that 5-HT2Rs may regulate the activity of 5-HT3Rs. The aim of this study was to determine whether co-activation of 5-HT2Rs prevents desensitization of 5-HT3Rs mediating the BJR in conscious rats. The principal findings were that (1) tachyphylaxis rapidly developed to the BJR-mediated hemodynamic responses elicited by successive injections of 5-HT3R agonists and (2) co-injection of the selective 5-HT2R agonist, α-methyl-5-HT, prevented tachyphylaxis to the BJR-mediated hemodynamic responses elicited by the 5-HT3R agonists. Additional studies provided evidence that (1) tachyphylaxis to the 5-HT3R agonists was not due to impairment of the central or efferent processing of the BJR, and (2) the pressor responses elicited by α-methyl-5-HT were not responsible for preventing tachyphylaxis to the BJR reflex responses elicited by 5-HT3R agonists. These results suggest that the loss of response to 5-HT3R agonists is due to desensitization of 5-HT3Rs on vagal afferents mediating the BJR and that co-activation of 5-HT2Rs prevents the desensitization of these 5-HT3Rs. © 2006 Elsevier B.V. All rights reserved.
Details
- Title: Subtitle
- Tachyphylaxis to 5-HT3-receptor-mediated activation of vagal afferents is prevented by co-activation of 5-HT2 receptors
- Creators
- Patrick J Lacolley - Department of Pharmacology, University of Iowa, Iowa City, IA 52242, United StatesJoy R Owen - Department of Physiology and Pharmacology, College of Veterinary Medicine, University of Georgia, Athens, GA 30602-7389, United StatesJames N Bates - Department of Anesthesia, University of Iowa, Iowa City, IA 52242, United StatesAlan Kim Johnson - Department of Pharmacology, University of Iowa, Iowa City, IA 52242, United StatesStephen J Lewis - Department of Physiology and Pharmacology, College of Veterinary Medicine, University of Georgia, Athens, GA 30602-7389, United States
- Resource Type
- Journal article
- Publication Details
- Brain research, Vol.1093(1), pp.105-115
- Publisher
- Elsevier
- DOI
- 10.1016/j.brainres.2006.03.090
- PMID
- 16712808
- ISSN
- 0006-8993
- eISSN
- 1872-6240
- Language
- English
- Date published
- 2006
- Academic Unit
- Psychological and Brain Sciences; Anesthesia; Neuroscience and Pharmacology; Health and Human Physiology
- Record Identifier
- 9984213423402771
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