[The nerve endings in contact with the parafollicular cells of the thyroid]. / Etude des terminaisons nerveuses au contact des cellules parafolliculaires de la thyroïde.

We studied nerve endings in the parafollicular cells of thyroid glands in necropsy examinations of 50 young males with no know thyroid disorder. The Jabonero and Maillet techniques. ultrastructural and morphology study were performed together with a statistical analysis of nerve endings. Optic microscope visualized preterminal and exceptionally terminal nerve endings located near parafollicular cells. Swellings of the axons without Schwann's cell sheath were identified close to the par follicular cells with electronic microscopy, these swellings had an ellipsoidal or spherical shape and laid close to the cellular membrane (30 nm). Three types of synaptic-like vesicles were found in these nerve endings. a) Abundant clear vesicles, generally spherical in shape (average diameter 50.40 +/- 5.91 nm); b) A few large granural vesicles with an electron-dense core (average diameter 105.49 +/- 9.98 nm); and c) Several small granular vesicles with an electron-dens core (average diameter 55.09 +/- 6.56 nm). Emphasis should be given to the finding of nerve endings (cholinergic-like, adrenergic-like and peptidergic-like nerve endings) in the parafollicular cells. We discuss their possible function.

Oxytocin-immunoreactive nerve cells in the supraoptic nucleus of the hypothalamus after treatment with histamine.

Immunohistochemical, morphometric and statistical methods were used to study oxytocin immunoreactive elements in the supraoptic nucleus (SON) of the hypothalamus of 180 male rats. Untreated rats, rats that were given either an intraperitoneal (ip) or intracerebroventricular (icv) injection of histamine (HA) (n = 40 each group) and control animals that received ip or icv injections of saline were included in our study. Oxytocin immunoreactive neurons and oxytocin-labelled nerve tracts were found in the SON of untreated animals. Treatment with saline either intracerebroventricular or intraperitoneally did not modify the oxytocin immunoreaction described for untreated animals. I.c.v. treatment with HA increased the numbers of oxytocin labelled elements. On the contrary, oxytocin immunoreaction after intraperitoneal treatment with HA was similar to that described for control and untreated animals. The morphometric and statistical studies confirmed these findings. The importance and signification of these results are discussed in this paper.

The vasopressin positive elements in the hypothalamic magnocellular nuclei of rats treated with histamine.

The vasopressin (AVP) positive elements of the hypothalamic supraoptic (SON) and paraventricular (PVN) nuclei, were investigated in 180 male rats through immunohistochemical, morphometric and statistical methods. The rats were subdivided in the next groups: 20 control rats; 40 rats treated with physiological saline intraperitoneal via (ip); 40 rats treated with physiological saline intracerebroventricular via (icv); 40 histamine (HA) treated rats, ip; and 40 HA treated rats, icv. The labeled nerve cells appear in the lateral part of the PNV and the SON of the control animals. These neurons have central nucleus and vasopressin positive cytoplasmic granulations. After the treatment with physiological saline, ip or icv, no alterations were observed. In HA treated rats, icv, numerous neurons strongly labeled were observed in these hypothalamic nuclei. Vasopressin positive nerve fibers and large droplets were also found both in the SON and in the PVN of these animals. The vasopressin positive material in the control rats and in HA treated rats, ip, is similar. The morphometric and statistical studies confirm these findings. The results are discussed in this paper.

The oxytocin positive elements in the hypothalamic magnocellular nuclei of rats treated with histamine.

The oxytocin positive elements of the hypothalamic supraoptic (SON) and paraventricular (PVN) nuclei, were instigated in 160 male rats through immunohistochemical, morphometric and statistical methods. The rats subdivided into five groups: 20 control rats; 20 rats treated with physiological saline intraperitoneal via (ip); 20 rats treated with physiological saline intracerebroventricular via (icv); 20 histamine (HA) treated rats, ip; and 20 HA treated rats, icv. Some labeled nerve cells appear, mainly, in the lateral part of the SON and the PVN of the control animals. These neurons have central nucleus and oxytocin positive cytoplasmic granulations. After the treatment with physiological saline, ip or icv, no alterations were observed. In HA treated rats, icv, numerous neurons and pathways were observed strongly labeled. Large droplets appear in the SON and in the PVN of these animals. In HA treated rats, ip, the oxytocin positive material is similar to that observed in the control rats. The morphometric and statistical studies confirm these findings. The results are discussed in this paper.