Calbindin Immunoreactivity in the Auricular Lobe and Interauricular Granular Band of the Cerebellum in Bullfrogs

Abstract

Calcium binding protein (CaBP) immunoreactivity in the cerebellum of bullfrogs was examined, concentrating on cells associated with the auricular lobe. While anti-calretinin and anti-parvalbumin also immunoreacted with the same cell populations, anti-calbindin exhibited the most robust and typical pattern of immunostaining. Calbindin immunoreactivity was observed in various populations of cells in the auricular lobe and interauricular granular band of the cerebellum, in the cerebellar peduncle, and in a bundle of interauricular commissural fibers which course through the dorsal, marginal, part of the molecular layer. Cells in the granular layer of the ventral part (i.e., corpus cerebelli) of the cerebellar plate were not CaBP-immunoreactive, nor were any fibers in the molecular layer of this cerebellar region. We believe that axons of CaBP-immunoreactive granule-like cells of the auricular lobes contribute to the formation of the interauricular fiber bundle, which corresponds to the lateral commissure of urodele amphibians. The pattern of calbindin immunoreactivity in the auricular lobes and marginal part of the cerebellar plate provides additional evidence that this cerebellar compartment, which is already present in tadpoles, has a distinct origin, biochemical characterization and connectivity and is separate from the compartment that forms the corpus cerebelli of frogs during metamorphosis.

Localization of Calbindin-D28k and Calretinin in the Brain of Dermophis Mexicanus (Amphibia: Gymnophiona) and Its Bearing on the Interpretation of Newly Recognized Neuroanatomical Regions

“…In gymnophionans this structure has not been clearly identified cytoarchitectonically [Kühlenbeck, 1922[Kühlenbeck, , 1975[Kühlenbeck, , 1978 and only some laterally located cells in r1 were proposed in Dermophis as a cerebellar nucleus because of their connections ]. In the other amphibian orders, it was corroborated that CB is constant in Purkinje cells in all species studied, particularly in the auricular lobes [Uray et al, 1998;Uray and Gona, 1999;Morona and González, 2009]. In Dermophis, clearly intense CBir cells appeared rostrally in the alar plate of r1.…”

“…At the same time, preabsorption of the anti-CR antibody under the same conditions with 100 g/ml CB (from chicken gut) did not affect staining. Furthermore, the primary antibodies used in our study have previously been employed in numerous amphibian species [Gábriel et al, 1998;Marín et al, 1998;Necchi et al, 1999;Uray and Gona, 1999;Edmonds et al, 2000;Milán and Puelles, 2000;Brox et al, 2003;González, 2008, 2009]. The same anti-CR has been tested via Western blot with brain extracts of several species of amphibians and labeled a single band of the expected molecular weight (29 kDa) that corresponds well with a similar band labeled in the lane of rat brain extract [Morona and González, 2008].…”

“…Specifically, CB is a good marker of Purkinje cells [Fortin et al, 1998;Schmidt et al, 2005Schmidt et al, , 2007, whereas CR is found mainly in other cell types as granular [Gall et al, 2003], unipolar, brush, and Lugaro cells Schiffmann et al, 1999], except in primates where some subpopulations of Purkinje cells are CRir [Fortin et al, 1998]. In all species of amphibians studied so far CB is present in Purkinje cells and some granule cells [Uray et al, 1998;Uray and Gona, 1999;Morona and González, 2009] and particularly in Rana but not in Xenopus laevis, and urodeles Purkinje cells contain CR [Necchi et al, 1999;Uray and Gona, 1999;Morona and González, 2009]. However, the cerebellum of gymnophionans is so poorly developed that several studies have suggested that it might be absent altogether [Fritzsch and Sontag, 1987;Roth et al, 1993].…”

Development of Tectal Connectivity across Metamorphosis in the Bullfrog (Rana catesbeiana)

“…CT ␤ -labeled cell bodies were observed in the CerN and in the lateral Cb (auricular lobe as defined by Uray and Gona [1999]; fig. 6 ).…”

“…During metamorphic climax and throughout postmetamorphic life, cell label in the Cb, in the same relative locations as in metamorphic climax, was visible bilaterally. In adults, small labeled cells were visible bilaterally in the region of the auricular lobe, but also more dorsally, in the corpus cerebelli (terminology of Uray and Gona [1999]; fig. 6 F, G).…”