- 作者: Chih-Chia Lai; Mei-Chi Chang; Hsun Hsun Lin
- 作者服務機構: Department of Pharmacology, Institute of Pharmacology and Toxicology, Tzu Chi University, and Department of Nursing, Tzu Chi College of Technology, Hualien, Taiwan, ROC
- 中文摘要: --
- 英文摘要: The present study was performed to examine the effectsof acute ethanol exposure on N-methyl-D-aspa rtate(NMDA)-induced responses and the development ofacute tolerance in rat rostral ventrolateral medulla(RVLM) in vivo and in vitro. Repeated microinjections ofNMDA (0.14 nmol) into the RVLM every 30 min causedreproducible increases in mean arterial pressure in ure-thane-anesthetized rats weighing 325-350 g. Intravenousinjections of ethanol (0.16 or 0.32 g,1 ml) inhibitedNMDA-induced pressor effects in a blood-concentration-dependent and reversible manner. The inhibitory effectof ethanol was reduced over time during continuousinfusion of ethanol or on the second injection 3.5 h afterprior injection of a higher dose of ethanol (0.32 g). A highdose of ethanol (0.32 g) had no significant effects on α-amino-3-hydroxy-5-methyl-4-isoxazolepropionic acid, γ-aminobutyric acid and glycine-induced changes in bloodpressure. In vitro studies showed that ethanol (10-100 mM) dose-dependently inhibited inward currentselicited by pressure ejection of NMDA (10 mM) in RVLMneurons of neonatal brainstem slice preparations. Whenthe superfusion time of ethanol (100 mM) was increasedto 50 min, its inhibitory effect decreased gradually after30-40 min in 60% of RVLM neurons examined. Thesedata suggested that ethanol inhibition and subsequenttolerance development is associated with changed sen-sitivity to NMDA in the RVLM, which may play importantroles in the ethanol regulation of cardiovascular func-tion.
- 中文關鍵字: --
- 英文關鍵字: --