Calcium, Ca-ATPase, Calmodulin, and Calbindin D-28KD Localization in Testis of (Anura: Leptodactylidae).

The intracellular localization of Ca2+, Ca2+-ATPase, Calmodulin, and Calbindin D-28KD have been studied in testes of the toad Leptodactylus chaquensis, using ultracytochemical and immunohistochemical techniques. The Ca2+ presences in the nucleus and into the mitochondria of the germ cells, together with the activity of Ca2+-ATPase detected in the nuclear envelope and mitochondrial crests, suggest the participation of this transporter in the storage of Ca2+. In Sertoli cells, Ca2+ deposits were also found in vesicles and lamellar bodies.

Effect of nervous stimulation on ovarian steroid secretion in amphibians.

In the present study, the effect of nerve stimulation on the secretory activity of the ovary of adult females was analyzed for the first time in amphibians. Results revealed that in Rhinella arenarum the stimulation of nerves that supply the gonad induced an increase in estradiol and progesterone secretion, this response showing differences during the reproductive cycle of the species. During the postreproductive period, an increase in estradiol secretion was observed while, in the reproductive period, progesterone secretion increased.

Effects of nerve stimulation on amphibian oviductal activity.

The present study describes, for the first time in an anuran amphibian, the nerve stimulation effects on the secretory and motor activity of the oviduct of adult females. The results reveal that in Rhinella arenarum oviducts, the epithelial and glandular secretory cells of the mucosa of the pars convoluta respond to nerve stimulation secreting the products synthetized and stored in their cytoplasm. The ultrastructural analysis showed that the cell content released is made up of granular, fibrillar and floccular material, exocytosis being the main secretory mechanism found in epithelial secretory cells, although apocrine and holocrine processes could also be observed.

Electron microscopy observations on testis and spermatozoa of Leptodactylus chaquensis (Anura, Leptodactylidae).

Scanning and transmission electron microscopy were used to investigate the fine structure of the testis and spermatozoa of toad Leptodactylus chaquensis. Our observations indicate that germinal compartment contains Sertoli (SC) and germ cells. The tight junctions and desmosomes among SC indicate the existence of an hematotesticular barrier in charge of maintaining the differences in the composition of the germinal and interstitial compartments.

Ultrastructure of the oviductal mucosa of Leptodactylus chaquensis. Analysis of the preovulatory and postovulatory periods.

In the present study we analysed the ultrastructural characteristics of the oviductal mucosa of Leptodactylus chaquensis during the preovulatory period and immediately after ovulation. Epithelial secretory cells, ciliated cells, basal cells and glandular secretory cells are described. During the preovulatory period, the oviduct exhibits its maximum degree of development at both the epithelial and the glandular levels, with numerous secretory cells that contain a large number of secretory granules whose contents are released into the oviductal lumen by apocrine and exocytotic secretory processes.

Innervation of amphibian reproductive system. Histological and ultrastructural studies.

In the present study we describe for the first time in anuran amphibians the histological and ultrastructural characteristics of innervation in the female reproductive organs. The observations in Rhinella arenarum revealed the presence of nerve fibers located predominantly in the ovarian hilium and in the oviduct wall. In both organs the nerves fibers are placed near blood vessels and smooth muscles fibers.