Mab anti-type I and Mab anti-zebrin II labelling in two siluriform fishes : the role of shared lineage versus shared function in polypeptide co-distributions

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Hoggatt, April Marie
Lannoo, Michael J.
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Thesis (M.S.)
Department of Physiology and Health Science
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Two monoclonal antibodies (mabs), the newly generated mab anti-type I and the previously documented mab anti-zebrin II, were reacted with brainstem sections of two ostariophysan siluriforms, the gymnotoid Rhamphichthys rostratus and the siluroid Ictalurus punctatus. Mab anti-type I recognizes a 47 kD polypeptide present in the dendrites and soma of projection neurons. Mab anti-zebrin II recognizes a 36 kD polypeptide present throughout the neuronal cytoplasm, including the axon. Strongly type I immunopositive cells include all cerebellar Purkinje cells, pyramidal cells of the nucleus medialis, electrosensory lateral line lobe, and tectum, pacemaker relay cells, Mauthner neurons, lateral line ganglion cells, and cells of the reticular formation, lateral reticular nucleus, and inferior olive. Weakly reactive type I cells include neurons in the torus semicircularis, medial and efferent octavolateralis nuclei, magnocellular and lateral tegmentum, and motor neurons of the Vth, V I Ith, and Xth cranial nerves. All type I positive cells are projection neurons. Zebrin II expression is restricted to subsets of two cell types which also express the type I antigen -- Purkinje cells and developing acousticolateralis pyramidal cells. Both of these neurons develop from the region of the rhombic lip. Thus, the mutual expression of the type I antigen can be explained by the shared function of projection neurons, while the common expression of the zebrin II antigen may be due to a shared embryological lineage.