Abstract:
The structural elements of the vascular zones are endothelial cells, basal lamina,
pericytes and neuroglial processes that can undergo structural remodelling according
to hormonal demand. The qualitative and the quantitative ultrastructural
characteristics and seasonal variations of these elements in the neurohypophysis of the
dromedary were investigated. The results showed a complex basal lamina, abundant
fibrillary elements at pericytes and an important membrane exchange in endothelial
cells. Quantitative analysis of neurovascular contacts did not show between seasons, a
significant variation in the number of nerve terminals contacting basal lamina,
however the mean number of glial processes significantly increased in winter (p =
0.037). We think that, as the animal is facing situations of combined stresses in
summer, high temperature, insolation…, that lead to increase water demand, these
would exert ultra-structural effect on the liberation of neuropeptides at perivascular to
decrease water output.
