- 作者: Wen-Bin Len; Samuel H.H. Chan; Julie Y.H. Chan
- 作者服務機構: Department of Biomedical Science, Chang-Gung College of Nursing, Taoyuan, Center for Neuroscience, National Sun Yat-sen University, Department of Medical Education and Research, Veterans General Hospital-Kaohsiung, Kaohsiung, Taiwan, Republic of China
- 中文摘要: --
- 英文摘要: The involvement of glutamatergic neurotransmission inthe rostral ventrolateral medulla (RVLM) in the suppres-sion of baroreflex bradycardia by the parabrachial nu-cleus (PBN) was investigated. Repeated electrical activa-tion of the PBN increased the concentration of glutamatein the dialysate collected from the RVLM. The same stim-ulation also suppressed baroreflex bradycardia in re-sponse to transient hypertension evoked by phenyleph-rine (5 ug/kg, intravenously). Microinfusion of L-gluta-mate (10, 50 or 100 uM) via the microdialysis probe intothe RVLM dose-dependently elicited a significant inhibi-tion of baroreflex bradycardia that paralleled the concen-tration and time course of the PBN-elicited elevation inextracellular glutamate in the RVLM. The suppression ofbaroreflex bradycardia elicited by microinjection of L-glutamate (1 nmol) into the RVLM was appreciably re-versed by coinjection of the NMDA receptor antagonist,dizocilpine (500 pmol), or the non-NMDA receptor antag-onist, 6-cyano-7-nitroquinoxaline-2,3-dione (50 pmol).These results suggest that an increase in the extracellu-lar concentration of glutamate and activation of bothNMDA and non-NMDA receptors in the RVLM may me-diate the suppression of baroreflex bradycardia by acti-vation of the PBN.
- 中文關鍵字: --
- 英文關鍵字: --