A Comparative Study of the Aminergic Structures in the Hypothalamus and the Hypophysis of Amphibian Larvae,with Special Reference to the Innervation of the Pars Distalis |
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Authors: | Stig Aronsson |
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Abstract: | The distribution and occurrence of the aminergic structures of the hypothalamus and the hypophysis of the investigated species are very similar, except for the pars distalis. In the tadpoles of the anuran species Rana temporaria, R. arvalis, R. dalmatina, R. escutenta, Bufo bufo and B. calamita, the pars distalis is aminergically innervated (the Falck-Hillarp technique), but these nerves disappear at the metamorphic climax. In the larvae of the urodelan species Triturus cristatus and T. vulgaris, the pars distalis is devoid of such nerves. Electron microscopical studies of R. temporaria, B. bufo and T. cristatus confirm these observations. A discussion of the functional significance of the pars distalis nerves and the phylogenetic role of the difference between anuran and urodelan species is given. |
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