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題名 | The Central Effect of Tizanidine on Reflex Bradycardia in Rats=Tizanidine的中樞作用對反射性徐脈之影響 |
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作者 | 劉鴻榮; 陳靜暉; 蔡麗雪; 馬明傑; Liu, Hung-jung; Chen, Ching-hui; Tsai, Li-hsueh; Ma, Ming-chieh; |
期刊 | 北醫學報 |
出版日期 | 19961200 |
卷期 | 25:2 1996.12[民85.12] |
頁次 | 頁1-7 |
分類號 | 415.13 |
語文 | eng |
關鍵詞 | 反射性徐脈; Tizanidine; Reflex bradycardia; |
中文摘要 | 本驗係探討由側腦室投與tizanidine對反射性徐脈之影響。實驗分為兩組:一組正常鼠,另一組為經由側腦室投與α-methyl-p-tyrosine methyl ester (120μg/kg)之兒茶酚胺耗竭鼠。正常鼠由側腦室投與tizanidine(0.1-1.0μg/kg)先導致血壓上升,接著產生與劑量相關的血壓下降與心跳減緩,此心血管反應在兒茶酚胺耗竭鼠則明顯地抑制。正常鼠預先投與tizanidine可增強由靜脈注射腎上腺素(0.5-2.5μg/kg)所產生的反射性徐脈現象,但tizanidine並不影響投與腎上腺素所造成的血壓上升效應。然而此由投與tizanidine所造成之反射性徐脈增強作用,在兒茶酚胺耗竭鼠則明顯地被減弱。由這些數據顯示,tizanidine可能參予中樞的兒茶酚胺機轉在急性血壓上升時,增強由壓力接受體反射途徑所產生的反射性徐脈作用,來調控心血管反應。 |
英文摘要 | Tizanidine, and imidazole-derived muscle relaxant, was investigated in the present research. The effects of tizanidine administration via intracerebroventricular (i.c.v.) system on cardiovascular functions were assessed in normal and catecholamine-depleted rats (tested 4 hr after intraventricular administration of 120 μg α-methyl-p-tyrosine methyl ester, α-MT). Intracerebroventricular administration of tizanidine (0.1-1.0 μg/kg) caused a dose-dependent depletion of the heart rate, while the arterial blood pressure was elevated first for a short period of time then decreased. In catecholamine-depleted rats, the above cardiovascular responses were inhibited. With regard to the reflex bradycardia produced by infusion of adrenaline (0.5-2.5 μg/kg) in rats, it was found that i.c.v. pretreatment of animals with tizanidine enhanced the adrenaline-induced reflex bradycardia in normal rats, but attenuated that in catecholamine-depleted rats. A parallel recording of arterial bolld pressure showed insignificant effect of tizamidine pretreatment on adrenaline-induced pressor response. thus, the data indicated that the effects of tizanidine act through a catecholaminergic mechanism to enhance the reflex bradycardia, which is mediated through baroreceptor reflexes in response to acute increase of blood pressure. |
本系統之摘要資訊系依該期刊論文摘要之資訊為主。