title: Bidirectional cardiovascular responses evoked by microstimulation of the amygdala in rats.
abstract: 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 GABAAreceptor 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.
authors.affiliation: Department of Physiology, Graduate School of Health and Sports Science, Juntendo University, 1-1 Hiraka-Gakuendai, Inzai, Chiba, 270-1695, Japan.
authors.forename: Ko
authors.initials: K
authors.lastname: Yamanaka
authors.affiliation: Department of Therapeutic Health Promotion, Kansai University of Health Sciences, 2-11-1 Wakaba, Kumatori, Sennan, Osaka, 590-0482, Japan.
authors.forename: Miwa
authors.initials: M
authors.lastname: Takagishi
authors.affiliation: Department of Physiology, Graduate School of Health and Sports Science, Juntendo University, 1-1 Hiraka-Gakuendai, Inzai, Chiba, 270-1695, Japan.
authors.forename: Jimmy
authors.initials: J
authors.lastname: Kim
authors.affiliation: Department of Biology, Faculty of Science, Ochanomizu University, 2-1-1 Otsuka, Bunkyo, Tokyo, 112-8610, Japan.
authors.forename: Sabine S
authors.initials: SS
authors.lastname: Gouraud
authors.affiliation: Department of Physiology, Graduate School of Health and Sports Science, Juntendo University, 1-1 Hiraka-Gakuendai, Inzai, Chiba, 270-1695, Japan. hwaki@juntendo.ac.jp.
authors.forename: Hidefumi
authors.initials: H
authors.lastname: Waki
mesh_terms: D000679:Amygdala / Q000187:drug effects / Q000503:physiopathology*; D000818:Animals; D062186:Arterial Pressure / Q000187:drug effects / Q000502:physiology; D017704:Baroreflex / Q000187:drug effects / Q000502:physiology; D002319:Cardiovascular System / Q000187:drug effects / Q000503:physiopathology*; D004558:Electric Stimulation / Q000379:methods; D058787:GABA-A Receptor Antagonists / Q000494:pharmacology; D006339:Heart Rate / Q000187:drug effects / Q000502:physiology; D008297:Male; D011311:Pressoreceptors / Q000378:metabolism; D051381:Rats; D017208:Rats, Wistar; D012018:Reflex / Q000187:drug effects / Q000502:physiology
chemical_list: D058787:GABA-A Receptor Antagonists
keywords: Amygdala; Arterial pressure; Baroreceptor reflex; Heart rate; Lesion