Ortiz-Delgado J B, Sarasquete C, Behrens A, González de Canales M L, Segner H
Animal and Plant Biology Department, Faculty of Sea Sciences, Pol. Río San Pedro s/n Apdo. 40, 11510, Cádiz, Puerto Real, Spain.
Aquat Toxicol. 2002 Oct 30;60(3-4):269-83. doi: 10.1016/s0166-445x(02)00006-1.
The presence and induction of cytochrome p4501A (CYP1A) in the brain of a teleost fish, the seabream, Sparus aurata, was studied. Cerebral CYP1A expression of control fish or fish exposed to various concentrations of 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD) was assessed at the enzyme activity level-measured as 7-ethoxyresorufin-O-deethylase; at the protein level-measured by means of Western blot and ELISA; and at the mRNA level-estimated by means of RT-PCR. Cellular localization of CYP1A in the brain tissue was studied using immunohistochemistry. In non-exposed control fish, expression of CYP1A could be demonstrated only in the olfactory bulbs. After TCDD exposure, the olfactory bulbs still showed the highest expression levels of CYP1A, however, other brain regions were now CYP1A-positive as well. Immunohistochemical examination of brain tissue sections from control fish demonstrated CYP1A immunoreactive fibers in the ventral telencephalon, in the glomerular layer of the olfactory bulbs, and in the endothelia of the cerebral vascular system. The same structures reacted positive in TCDD-exposed fish, but cell bodies and fibers from additional brain areas including telencephalon, diencephalon, mesencephalon and cerebellum showed CYP1A immunostaining. In the pituitary of TCDD-treated fish, putative GTH cells were positive for CYP1A, whereas in control fish no staining of the adenohypophysis was observed. The present findings provide evidence for basal expression of CYP1A in the telencephalon of Sparus aurata, and for the presence of inducible CYP1A in all other major brain regions, including the pituitary.
研究了硬骨鱼金头鲷（Sparus aurata）脑中细胞色素P4501A（CYP1A）的存在及诱导情况。通过以下方式评估对照鱼或暴露于不同浓度2,3,7,8 - 四氯二苯并 - 对 - 二恶英（TCDD）的鱼脑中CYP1A的表达：酶活性水平——以7 - 乙氧基异吩恶唑酮 - O - 脱乙基酶来衡量；蛋白质水平——通过蛋白质免疫印迹法和酶联免疫吸附测定法来检测；mRNA水平——通过逆转录聚合酶链反应来估算。利用免疫组织化学研究了CYP1A在脑组织中的细胞定位。在未暴露的对照鱼中，仅在嗅球中可检测到CYP1A的表达。TCDD暴露后，嗅球中CYP1A的表达水平仍然最高，然而，其他脑区现在也呈CYP1A阳性。对对照鱼脑组织切片的免疫组织化学检查显示，腹侧端脑、嗅球的肾小球层以及脑血管系统的内皮细胞中有CYP1A免疫反应性纤维。在TCDD暴露的鱼中，相同结构呈阳性反应，但包括端脑、间脑、中脑和小脑在内的其他脑区的细胞体和纤维也显示出CYP1A免疫染色。在TCDD处理的鱼的垂体中，假定的促性腺激素细胞CYP1A呈阳性，而在对照鱼中未观察到腺垂体有染色。目前的研究结果为金头鲷端脑中CYP1A的基础表达以及包括垂体在内的所有其他主要脑区中可诱导的CYP1A的存在提供了证据。
