利用紅藻胺酸引發抽搐之幼鼠來探討神經??和細胞激素之表現

The Expression of Neuropeptides and Cytokines in the Neonatal Rats with Kainate-Induced Seizure

陳素蓮

指導教授 ： 呂思潔

臺北醫學大學/醫學院/細胞及分子生物研究所/碩士(2000年)

摘要

親皮質素釋放激素（CRH）是一種由41個胺基酸所組成的神經??，它也是下視丘-腦下垂體-腎上腺皮質軸線的主要調節者，可導致腦下垂體合成分泌ACTH進而刺激腎上腺皮質分泌醣皮質固醇。已經有文獻指出CRH在人類幼年癲癇或幼鼠痙?的發生扮演相當重要的角色。因而有學者提出「CRH過量產生導致癲癇發生」之假說，另外，於幼鼠腦室注射CRH比起成鼠能更快地引發痙?。近年來許多研究發現細胞激素具有調節內分泌的功能，並參與許多中樞神經系統疾病的過程進展，基於上述這些原因，為更能深入了解CRH在癲癇所參與的病理機轉，我們利用紅藻胺酸（KA）引發幼鼠產生抽搐藉以探討CRH和細胞激素在周邊或腦中的表現情形。實驗結果指出：在注射KA的P30天幼鼠其血漿中CRH濃度（46.62±30.32 ng/ml, p=0.0303）明顯地較控制組為高，然而在注射KA的P7天、P14天幼鼠其血漿中CRH濃度和控制組相比卻無統計上的差異。在注射DM的P30天幼鼠其血漿中CRH濃度明顯地較注射KA的幼鼠其血漿中CRH濃度為低。另一方面，利用RT-PCR方法來探討神經??（CRH、POMC）和細胞激素（IL-1β、IL-6、TNF-α、IFN-γ）在不同腦區的mRNA表現情形。在注射KA的P30天幼鼠的大腦皮質其CRH、IL-1β、IL-6的表現明顯地比控制組為高；此外，在注射KA的P7天幼鼠的大腦皮質其CRH的表現也明顯地比控制組為高。這些實驗結果顯示：CRH和細胞激素IL-1β、IL-6在幼鼠痙?上可能具有免疫調節的功能。

關鍵字

親皮質素釋放激素 ； 紅藻胺酸

並列摘要

Corticotropin-Release Hormone (CRH), a 41 amino acid neuropeptide, is a major regulator of the HPA axis, which release leads to pituitary production of adrenocorticotropic hormone (ACTH) followed by glucocorticoid secretion by the adrenal cortex. CRH has been implicated as an important neuro-hormone participating in seizure generation particularly in early life of both human and animals. It is possible that not only CRH presents as a pro-convulsant in the developing brain, but in seizure activity, it may elicit release of CRH which could further enhance the seizure intensity. To address this issue we measured the plasma CRH concentration in developing rats received kainic acid (KA), a convulsant agent which exerts behavioral and electrophysiological seizure activities by activating at kainate receptor and N-methyl-D-aspartate (NMDA) receptor. We also determine whether the NMDA receptor antagonist-dextromethorphan (DM) could attenuate release of CRH on KA-induced seizure on the release of CRH. These results demonstrated that significantly increase circulating CRH concentration (46.62±30.32 ng/ml, p=0.0303) was observed in P30 rat but not on P7 and P14 rat. Injection of DM could effectively attenuate the KA-induced seizure intensity as well as the CRH level (p=0.0026) on P30 rat. Furthermore, mRNA expression of neuropeptide (CRH and POMC) and cytokines (IL-6, IL-1β, TNF-α, and IFN-γ) from different brain region are analyzed by RT-PCR. In P30 rat cortex, CRH, IL-6 and IL-lβ mRNA expression were significantly increased in KA-induced seizure as compared to control. In addition, CRH mRNA is also significantly increased in P7 rat cortex in KA-induced seizure as compared to control. These data support the CRH and cytokines (IL-lβ and IL-6) may have immunoregulatory role in seizure activity.

參考文獻

參考文獻 Allsopp T.E., Wyatt S., Paterson H.F., Davies A.M., (1993) The protooncogene bcl-2 can selectively rescue neurotrophic factor-dependant neurons from apoptosis. Cell 73, 295-307.

Allsopp T.E., Kiselev S., Wyatt S., Davies A.M., (1995) Role of bcl-2 in the. brain-derived neurotrophic factor survival response. Eur. J. Neurosci. 7, 1266-1272.

Baram T.Z., Mitchell W.G., Snead III O.C., Horton E.J., Saito M., (1992) Brain-adrenal axis hormones are altered in the CSF of infants with massive infantile spasms. Neurology 42,1171-1175

Baram T.Z., Schultz L., (1995) ACTH dose not control neonatal seizures induced by administration of exogenous corticotropin-releasing hormone. Epilepsia 36, 174-178.

Ben-Ari Y., Tremblay E., Ottersen O.P., (1980) Injection of Kainic acid into the the amygdaloid complex of the rat: an electrographic, clinical and histological study in relation to the pathology of epilepsy. Neurosci 5, 515-528.