臺灣博碩士論文加值系統

河豚(四齒魨科)始載於宋開寶本草,中醫藥臨床用為補虛,去濕氣,理腰
腳, 去痔疾及殺蟲.河豚毒素(以下簡稱TTX)為河豚類之主要毒性成份.本
研究主旨在於探討TTX對大鼠體溫的影響,以及是否經由體溫調節中樞-下
視丘視前區(preoptic anterior hypothalamus)之serotoninergic ystem
或其它 monoaminergic system來影響體溫.大鼠腹腔注射TTX,會產生肛溫
下降之現象,並且隨著注射劑量 (TTX 1-7 ug/kg)增加,肛溫下降程度亦增
加.而重複給藥 (TTX 5 ug/kg,i.p.)並不會降低TTX的降溫作用.若直接投
予小劑量 (TTX 0.003 or 0.005ug)於下視丘,仍有降溫反應.另外,於下視
丘部位注入Lipopolysaccharide(LPS,4 ug)所誘導之高燒現象,可因腹腔
注入TTX而減退.利用[生物體溫調節及相關生理參數自動化分析系統]偵測
得知 TTX對大鼠之降溫作用亦由於新陳代謝作用降低,即體內產熱減少,且
表皮溫度升高即血管擴張,熱散失增加所致.利用伏安法測量TTX 對大鼠下
視丘視前區中serotonin及dopamine釋放量的影響並探討其與環境溫度之
關係.實驗發現,TTX引起降溫作用的同時, 也伴隨著下視丘中serotonin及
dopamine釋放量的降低. 若事先在大鼠側腦室注入5,7-
dihydroxytryptamine(200 ug in 10 ul) 破壞腦部 serotonin 神經元,
或腹腔注射p-chlorophenylalanine(200mg/kg)抑制突觸前serotonin 之
生合成,兩者所引起之神經細胞中serotonin 空乏的現象, 並不會使TTX
之降溫作用喪失.由此推測, TTX 可能經由作用在 serotonin 之突觸後神
經元細胞, 而引起降溫作用.綜合實驗結果顯示, TTX之降溫或退熱作用,
乃由於降低新陳代謝率及引起週邊血管擴張所致;並且可能經由作用在下
視丘血壓胺突觸前接受體機轉(presynaptic serotoninergic receptor
mechanisms) 或其它單胺類神經傳導物質而引起降溫.

Tetraodonidae was first described in Kai-Pao Pen-Tsao at Sung
Dynasty,and was used as analgestic,for antigoat,hemorrhoid
andarasite.There were about 36 species of Monacanthidae iniwan,
all of these species were almost toxic fish. Intraperitoneal
administration of TTX(Tetrodotoxin)(1-7ug/kg) produced dose-
dependent decrease in colonic temperature inats. Daily
injection of TTX(5 ug/kg,i.p.) for 4 days,it did not attenuated
the TTX-induced hypothermia.TTX also decreased theyperthermia
produced by LPS(lipopolysaccharide) for 60 mins. Direct
administration of small amount(0.003 ug/ul or 0.005 ug/ul) of
TTX into the rat''s hypothalamus also producedame amount of
hypothermia. The TTX-induced hypothermia was not affected by
depletion ofrain serotonin produced by 5,7-DHT(5,7-
dihydroxytryptamine) orCPA(p-chloro-phenylalanine) and 6-OHDA(6-
hydroxydopamine). The TTX-induced hypothermia was due to
decreased metabolismnd increased heat loss( or skin
vasodilation). In vivo voltammetrical measurement also revealed
that TTXdministration enhanced the 5-HT and dopamine release in
thepothalamus of rat brain. These results suggest that TTX may
act through theonoaminergic mechanism in the brain to influence
the effect ofpothermia.