Fiber connections of the corpus glomerulosum in a teleost, Navodon modestus.

Fiber connections of the corpus glomerulosum (CG) in a teleost, Navodon modestus, were studied by means of horseradish peroxidase (HRP) and the Fink-Heimer methods. The CG is divided into a pars anterior (GA) and a pars rotunda (GR). Both the GR and the GA have the same cell components and glomeruli. The GR is composed of four layers arranged concentrically around a central fiber net in the following order (Ito and Kishida, '75): a glomerular layer, a fibrous layer, a small-cell layer, and a peripheral fibrous capsule including large cells. The GA consists of a central glomerular layer and a peripheral small-cell layer which contains some large cells. Following HRP injections into the GR, HRP-positive cells were found bilaterally in the nucleus corticalis and ipsilaterally in the nucleus intermedius of Bricker ('29). Lesions of the nucleus corticalis produced degenerating terminals bilaterally in glomeruli in the CG. The course of the fiber connections was coincident with that of the commissura horizontalis. Lesions of the nucleus intermedius resulted in degenerating terminals in the fibrous layer of the GR and the small-cell layer of the GA. Following the destruction of the GR, degenerating terminals occurred in the ipsilateral lobus inferior. Both small and large cells in the ipsilateral CG were labeled after HRP injections into the lobus inferior.