Abstract | BACKGROUND: Cardiac vagal preganglionic neurons (CVPN) are responsible for the tonic, reflex and respiratory modulation of heart rate (HR). Although CVPN receive GABAergic and glutamatergic inputs, likely involved in respiratory and reflex modulation of HR respectively, little else is known regarding the functions controlled by ionotropic inputs. Activation of g-protein coupled receptors (GPCR) alters these inputs, but the functional consequence is largely unknown. The present study aimed to delineate how ionotropic GABAergic, glycinergic and glutamatergic inputs contribute to the tonic and reflex control of HR and in particular determine which receptor subtypes were involved. Furthermore, we wished to establish how activation of the 5-HT1A GPCR affects tonic and reflex control of HR and what ionotropic interactions this might involve. RESULTS: CONCLUSIONS: We conclude that activation of GABAA receptors set the level of HR whereas AMPA to a greater extent than NMDA receptors elicit baroreflex changes in HR. Furthermore, activation of 5-HT1A receptors evokes bradycardia and enhances baroreflex changes in HR due to interactions with glycinergic neurons involving strychnine receptors. This study provides reference for future studies investigating how diseases alter neurochemical inputs to CVPN.
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Authors | Cara M Hildreth, Ann K Goodchild |
Journal | BMC neuroscience
(BMC Neurosci)
Vol. 11
Pg. 128
(Oct 13 2010)
ISSN: 1471-2202 [Electronic] England |
PMID | 20939929
(Publication Type: Journal Article, Research Support, Non-U.S. Gov't)
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Chemical References |
- Excitatory Amino Acid Agonists
- Excitatory Amino Acid Antagonists
- Glycine Agents
- Receptors, GABA
- Receptors, Glutamate
- Receptors, Glycine
- Receptor, Serotonin, 5-HT1A
- Strychnine
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Topics |
- Animals
- Baroreflex
(physiology)
- Blood Pressure
(physiology)
- Decerebrate State
(physiopathology)
- Excitatory Amino Acid Agonists
(pharmacology)
- Excitatory Amino Acid Antagonists
(pharmacology)
- Glycine Agents
(pharmacology)
- Heart
(innervation, physiology)
- Heart Rate
(physiology)
- Male
- Medulla Oblongata
(physiology)
- Microinjections
- Rats
- Rats, Sprague-Dawley
- Receptor, Serotonin, 5-HT1A
(drug effects, physiology)
- Receptors, GABA
(drug effects, physiology)
- Receptors, Glutamate
(drug effects, physiology)
- Receptors, Glycine
(drug effects, physiology)
- Strychnine
(pharmacology)
- Synaptic Transmission
(physiology)
- Vagus Nerve
(physiology)
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