1. Suppressed baroreflex peripheral arc overwhelms augmented neural arc and incapacitates baroreflex function in rats with pulmonary arterial hypertension
- Author
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Keimei Yoshida, Kana Fujii, Takuya Nishikawa, Keita Saku, Tomohito Ishikawa, Masako Shinoda, Takeshi Tohyama, Kohtaro Abe, Hiroyuki Tsutsui, Takuya Kishi, Yasuhiro Oga, Yukimitsu Kuwabara, and Kenji Sunagawa
- Subjects
Male ,medicine.medical_specialty ,Sympathetic nervous system ,Sympathetic Nervous System ,Physiology ,medicine.medical_treatment ,Blood Pressure ,030204 cardiovascular system & hematology ,Baroreflex ,Rats, Sprague-Dawley ,Arc (geometry) ,03 medical and health sciences ,0302 clinical medicine ,Physiology (medical) ,Negative feedback ,Internal medicine ,medicine ,Animals ,Arterial Pressure ,Saline ,Pulmonary Arterial Hypertension ,Nutrition and Dietetics ,business.industry ,Arterial baroreflex ,General Medicine ,Rats ,Peripheral ,Blood pressure ,medicine.anatomical_structure ,Cardiology ,business ,030217 neurology & neurosurgery - Abstract
NEW FINDINGS What is the central question of this study? The impact of pulmonary arterial hypertension on open-loop baroreflex function, which determines how powerfully and rapidly the baroreflex operates to regulate arterial pressure, remains poorly understood. What is the main finding and its importance? The gain of the baroreflex total arc, indicating the baroreflex pressure-stabilizing function, is markedly attenuated in rats with monocrotaline-induced pulmonary arterial hypertension. This is caused by a rightward shift of the baroreflex neural arc and a downward shift of the peripheral arc. These findings contribute greatly to our understanding of arterial pressure regulation by the sympathetic nervous system in pulmonary arterial hypertension. ABSTRACT Sympathoexcitation has been documented in patients with established pulmonary arterial hypertension (PAH). Although the arterial baroreflex is the main negative feedback regulator of sympathetic nerve activity (SNA), the way in which PAH impacts baroreflex function remains poorly understood. In this study, we conducted baroreflex open-loop analysis in a rat model of PAH. Sprague-Dawley rats were injected with monocrotaline (MCT) s.c. to induce PAH (60 mg kg-1 ; n = 11) or saline as a control group (CTL; n = 8). At 3.5 weeks after MCT injection, bilateral carotid sinuses were isolated, and intrasinus pressure (CSP) was controlled while SNA at the coeliac ganglia and arterial pressure (AP) were recorded. To examine the static baroreflex function, CSP was increased stepwise while steady-state AP (total arc) and SNA (neural arc) responses to CSP and the AP response to SNA (peripheral arc) were measured. Monocrotaline significantly decreased the static gain of the baroreflex total arc at the operating AP compared with CTL (-0.80 ± 0.31 versus -0.22 ± 0.22, P
- Published
- 2019
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