Folgueira Mónica, Anadón Ramón, Yáñez Julián
Department of Cell and Molecular Biology, Faculty of Sciences, University of A Coruña, 15071 A Coruña, Spain.
J Comp Neurol. 2003 Oct 27;465(4):604-19. doi: 10.1002/cne.10879.
Salmonids are a group of teleosts with a nonspecialized gustatory system. With the aim of describing the gustatory connections in a member of this group, we carried out tract-tracing experiments using the lipophilic carbocyanine dye 1,1'-dioctadecyl 3,3,3',3'-tetramethylindocarbocyanine perchlorate (DiI) in fixed brains of the rainbow trout (Oncorhynchus mykiss). The neural tracer was applied to the primary viscerosensory column, secondary gustatory visceral nucleus (SGN), torus lateralis (TL), and tertiary gustatory nucleus (TGN), the dorsal part of the ventral area of the telencephalon (dorsal-Vv), and the medial area of the dorsal telencephalon (Dm). The primary viscerosensory column projects mainly to the SGN. DiI application to the SGN showed a bilateral and reciprocal connection with the TGN and a rostral portion of the nucleus of the lateral hypothalamic recess. The application of DiI in the dorsal-Vv and Dm at levels rostral to the anterior commissure led to labeling of a restricted group of diencephalic neurons in the TGN and sending dendrites to the TL. DiI application to the TL/TGN anterogradely labeled fibers that coursed in the medial forebrain bundle innervating the precommissural portion of the dorsal-Vv and Dm. Caudally, this type of application led to labeling of fibers in the viscerosensory column and perikarya in the SGN. Tract-tracing results showed direct projections from the diencephalic and rhombencephalic gustatory nuclei to the telencephalon. There was a direct and reciprocal connection between the SGN and the ventral telencephalon. The results showed that the gustatory connections of the trout are similar to those of teleosts, with highly specialized gustatory centers as in cyprinids and ictalurids, and to that observed in the percomorph tilapia, thus demonstrating a basic organization that is shared by most teleosts.
鲑科鱼类是一群具有非特化味觉系统的硬骨鱼。为了描述该类群中一个成员的味觉联系，我们在虹鳟（Oncorhynchus mykiss）的固定脑标本中，使用亲脂性花青染料1,1'-二辛基-3,3,3',3'-四甲基吲哚羰花青高氯酸盐（DiI）进行了束路追踪实验。将神经示踪剂应用于初级内脏感觉柱、次级味觉内脏核（SGN）、外侧隆起（TL）和三级味觉核（TGN）、端脑腹侧区的背侧部分（背侧-Vv）以及端脑背侧的内侧区（Dm）。初级内脏感觉柱主要投射到SGN。将DiI应用于SGN显示其与TGN以及下丘脑外侧隐窝核的 Rostral部分存在双侧和相互连接。在背侧-Vv和Dm中，于前连合前方水平应用DiI，导致TGN中一组特定的间脑神经元被标记，并向TL发出树突。将DiI应用于TL/TGN可顺行标记在前脑内侧束中走行、支配背侧-Vv和Dm的连合前部分的纤维。在尾侧，这种应用导致内脏感觉柱中的纤维和SGN中的核周体被标记。束路追踪结果显示，间脑和后脑味觉核与端脑之间存在直接投射。SGN与腹侧端脑之间存在直接和相互连接。结果表明，虹鳟的味觉联系与硬骨鱼相似，具有与鲤科鱼类和鲇形目鱼类一样高度特化的味觉中枢，也与鲈形目罗非鱼中观察到的情况相似，从而证明了大多数硬骨鱼共有的基本组织结构。
