Departamento de Biodiversidad y Biología Experimental, Facultad de Ciencias Exactas y Naturales, Universidad de Buenos Aires, Ciudad Universitaria (C1428EHA), Buenos Aires, Argentina.
J Fish Biol. 2014 Sep;85(3):605-20. doi: 10.1111/jfb.12446. Epub 2014 Jun 27.
This research describes the pineal complex histology in juvenile and adult Cichlasoma dimerus, and the effect of different photoperiods on its cell morphology. In both juveniles and adults, the pineal complex of C. dimerus has three components: the pineal organ, consisting of a pineal vesicle (PV) and a pineal stalk, the parapineal organ and the dorsal sac. Although a strong morphological resemblance exists between the two stages, different synthesis patterns of cone and rod opsins were detected in the two life stages. An effect of the photoperiod length was observed on putative pinealocytes' activity from the PV, measured indirectly through nuclear area morphometry. Individuals exposed to a natural photoperiod (14L:10D) had smaller nuclear areas (mean ± s.e. = 13·82 ± 1·52 µm(2) ) than those exposed to a short photoperiod (8:16) (21·45 ± 2·67 µm(2) ; P < 0·001). Eventually, the nuclear area of pinealocytes could be used as a putative indicator of melatonin synthesis in fishes where it is difficult to obtain plasma samples, e.g. due to its small size or age. This work constitutes one of the few comparative descriptions of the pineal complex of juvenile and adult teleost and suggests potential approaches for the study of melatonin synthesis in fish larvae or small adult fishes.
本研究描述了幼年和成年 Cichlasoma dimerus 的松果体复合体组织学，以及不同光周期对其细胞形态的影响。在幼年和成年个体中，C. dimerus 的松果体复合体有三个组成部分：松果腺，由松果囊 (PV) 和松果柄组成；副松果腺；和背囊。尽管这两个阶段存在很强的形态相似性，但在两个生命阶段检测到了锥体和棒体视蛋白的不同合成模式。通过对松果囊中假定的松果体细胞活性的核面积形态测量，观察到光周期长度对其有影响。暴露在自然光周期 (14L:10D) 下的个体的核面积 (平均值 ± 标准误 = 13.82 ± 1.52 µm²) 小于暴露在短光周期 (8:16) 下的个体 (21.45 ± 2.67 µm²；P < 0.001)。最终，松果体细胞的核面积可以作为鱼类中褪黑素合成的一个潜在指标，因为在鱼类中很难获得血浆样本，例如由于其体型小或年龄小。这项工作是对幼年和成年硬骨鱼的松果体复合体进行比较描述的少数研究之一，为研究鱼类幼虫或小型成鱼的褪黑素合成提供了潜在的方法。
