Kemnitz C P, Fox L M, McNulty J A
Department of Pharmacology, Loyola University Stritch School of Medicine, Maywood, Illinois 60135.
J Morphol. 1990 May;204(2):197-208. doi: 10.1002/jmor.1052040208.
The morphology and anatomical relationship of the paraphysis, anterior choroid plexus, and endolymphatic tubules of Hyla versicolor suggest that these structures may act as a functional unit to regulate composition of the cerebrospinal fluid (CSF). Ependymal cells of both the paraphysis and the choroid plexus exhibit ultrastructural features (an extensive microvillar border, large intercellular spaces containing an amorphous material, and apically located mitochondria) which indicate active exchange between the blood and CSF. Mast cells (which may play a role in regulating vascular permeability) also occur on the brush border. The tubules of the endolymphatic sacs were found to lie in close relation with the dorsal portion of the paraphysis. The endolymphatic organ is known to play a role in systemic buffering during respiratory acidosis and may influence Na/K fluxes via calcium release. The association of the paraphysis with the endolymphatic tubules may therefore represent an important mechanism for ion regulation in the CSF of amphibians. The ultrastructure of the pineal organ agrees with descriptions for other species. No pineal stalk was present. Photoreceptor inner and outer segments project into a central lumen continuous with the third ventricle. Outer segments show signs of disorganization. Photoreceptor/neural dendrite contacts involve synaptic ribbons and conventional synapses.
变色树蛙的旁突体、前脉络丛和内淋巴管的形态及解剖关系表明，这些结构可能作为一个功能单元来调节脑脊液（CSF）的成分。旁突体和脉络丛的室管膜细胞均呈现超微结构特征（广泛的微绒毛边界、含有无定形物质的大细胞间隙以及顶端定位的线粒体），这表明血液与脑脊液之间存在活跃的交换。肥大细胞（可能在调节血管通透性方面发挥作用）也出现在刷状缘。发现内淋巴囊的小管与旁突体的背侧部分密切相关。已知内淋巴器官在呼吸性酸中毒期间的全身缓冲中发挥作用，并且可能通过钙释放影响钠/钾通量。因此，旁突体与内淋巴管的关联可能代表两栖动物脑脊液中离子调节的重要机制。松果体的超微结构与其他物种的描述一致。不存在松果体柄。光感受器的内段和外段伸入与第三脑室连续的中央腔。外段显示出紊乱的迹象。光感受器/神经树突接触涉及突触带和传统突触。
