Dermo-epithelial interactions during the development of cutaneous gland anlagen in Amphibia: a light and electron microscope study on several species with some cytochemical findings
Delfino, G.; Brizzi, R.; Calloni, C.
Zeitschrift für Mikroskopisch-Anatomische Forschung 99(2): 225-253
1985
ISSN/ISBN: 0044-3107 PMID: 4024699 Document Number: 261319
The precocious stages of development of the amphibian cutaneous glands were described in 12 species Bombina variegata pachypus, Bufo bufo, Discoglossus pictus, Hyla arborea, Rana graeca, R. temporaria, Ambystoma mexicanum, Euproctus platycephalus, Salamandra salamandra, Salamandrina terdigitata, Triturus alpestris and T. cristatus (6 Anura and 6 Urodela). During these morphogenetic phases the gland anlagen segregate from epidermis and establish stromal relationships with the dermis. Particular consideration was given to the serous (or granulous) anlagen during the study, since their corresponding fully developed glands present significant morphofunctional differences in the 2 orders. Isolation of the gland buds results not only from proliferation processes and kinesis in their blastocytes, but also from interactions between these cells and connective tissue cells, which, through coordinated processes of synthesis and demolition, remodel the junctional structure at the dermoepithelial interface. The aspects of these interactions are compared with examples of epithelial mesenchymal cooperations described during the morphogenesis of exocrine glands in homeotherm vertebrates. The research was carried out on a wide range of species and emphasizes that the isolation process, which meets resistance from a dense layer of dermis, proceeds differently in the 2 orders, though they have similar cytological mechanisms at disposition. In the Anura, where proliferative phenomena prevail, isolation is achieved by active invasion into the dermis on the part of the anlagen; in the serous gland buds the process evolves rather slowly and consequently their secretory cytodifferentiation starts within an epidermal microenvironmnet. Isolation in the Urodela is very rapid: a stromal cleft rises from the dermis within the thickness of the epidermis, following migration of the peripheral gland blastocytes, wich converge towards the anlage apex.