Neuronal increase in the trout (Salmo trutta fario) spinal cord during development
Alfei, L.; Sesti, G.
Cellular and Molecular Biology 30(5): 471-478
1984
ISSN/ISBN: 0145-5680 PMID: 6529739 Document Number: 238225
Two groups of motoneurons are recognizable in cross-sections of the trout spinal cord, the dorsomedian and ventrolateral. Motoneurons belonging to each group were counted throughout development starting from pre-hatching stages. Two regions were considered, the trunk and the caudal, that corresponded in length. Evidence is shown of a different degree of differentiation in the trunk region with respect to the caudal. In the latter, in fact, the motoneuron number remains almost constant until the fingerling stage, whereas a neuron increase is observed in the trunk region starting from embryonic stage 23. In both regions a neuronal decrement is observed in the alevin stage. The data are correlated to the differentiation and number of red and white muscle fibers and to the acquisition of the trout-specific type of motility, the subcarangiform mode of swimming.