Bidirectional cardiovascular responses evoked by microstimulation of the amygdala in rats

Although the amygdala is known as a negative emotion center for coordinating defensive behaviors, its functions in autonomic control remain unclear. To resolve this issue, we examined effects on cardiovascular responses induced by stimulation and lesions of the amygdala in anesthetized and free-movi...

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Bibliographic Details
Published in:The journal of physiological sciences 2018-05, Vol.68 (3), p.233-242
Main Authors: Yamanaka, Ko, Takagishi, Miwa, Kim, Jimmy, Gouraud, Sabine S., Waki, Hidefumi
Format: Article
Language:English
Subjects:
Amygdala
Amygdala - drug effects
Amygdala - physiopathology
Animals
Arterial pressure
Arterial Pressure - drug effects
Arterial Pressure - physiology
Autonomic nervous system
Baroreceptor reflex
Baroreflex - drug effects
Baroreflex - physiology
Blood pressure
Cardiovascular system
Cardiovascular System - drug effects
Cardiovascular System - physiopathology
Electric Stimulation - methods
GABA
GABA-A Receptor Antagonists - pharmacology
Heart beat
Heart rate
Heart Rate - drug effects
Heart Rate - physiology
Lesion
Male
Microinjection
Original Paper
Pressoreceptors - metabolism
Rats
Rats, Wistar
Reflex - drug effects
Reflex - physiology
Rodents
γ-Aminobutyric acid A receptors
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Summary:Although the amygdala is known as a negative emotion center for coordinating defensive behaviors, its functions in autonomic control remain unclear. To resolve this issue, we examined effects on cardiovascular responses induced by stimulation and lesions of the amygdala in anesthetized and free-moving rats. Electrical microstimulation of the central nucleus of the amygdala (CeA) induced a gradual increase in arterial pressure (AP) and heart rate (HR), whereas stimulation of adjacent nuclei evoked a phasic AP decrease. The gain of the baroreceptor reflex was not altered by CeA stimulation, suggesting that CeA activity increases both AP and HR by resetting baroreceptor reflex function. Disinhibition of GABAergic input by amygdalar microinjection of the GABAA receptor antagonist induced robust increases in AP and HR. Furthermore, bilateral electrolytic lesions of CeA evoked consistent AP increases over the light/dark cycle. These results suggest that the amygdala exerts ‘bidirectional’ autonomic control over the cardiovascular system.
ISSN:1880-6546
1880-6562
DOI:10.1007/s12576-017-0523-2