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.