CHANGES IN RESPONSE TO OXYTOCIN FOLLOWED THROUGHOUT ONTOGENESIS IN 2 ANURAN SPECIES

The response to oxytocin of two anuran amphibians Rana ridibunda and Bufo viridis was studied throughout ontogenesis. The response of R. ridibunda tadpoles to oxytocin started at the stage of 2 legs, increased with maturation of the tadpole, reaching its climax upon metamorphosis and dropping thereafter, whether kept on wet ground or in H2O. In B. viridis the response started at the tadpole stage, reaching its climax at the juvenile stage, where this response was much higher than in R. ridibunda. In both species, post-metamorphic growth affected the response to oxytocin, causing it to decline. A positive correlation was found between these 2 phenomena. Some differences were found in the response to oxytocin between summer and winter frogs. The response in vitro of the bladder of adult R. ridibunda was higher than that of the juveniles. The response in vitro of ventral epidermis was higher in juveniles than in adults. The response in vitro of dorsal epidermis was higher in the adult frogs. Summer frogs'' epidermis responded less than that of the winter frogs.