[Coexpression of gonadotropin inhibitory hormone and gonadotropin releasing hormone neurons in the preoptic area of hypothalamus in the phases of estrous cycle of the ewe]

The aim of the present study was to evaluate the colocalization of GnlH and GnRH neurons in the ewe preoptic area [POA] of hypothalamus during the phases of estrous cycle. Three ewes in three phases of proestrus, estrus and luteal of estrous cycle [n=9] were selected and based on their estrous cycle phase, the number of GnlH and GnRH neurons and percent of these two neuropeptides colocalization in POA were estimated by using immunohistochemistry method. GnlH and GnRH neurons were present in the POA during the different phases of ewe estrous cycle and their colocalization was observed. The number of GnlH neurons in luteal phase was substantially more than proestrus and estrus phases [P<0.01]. However, there was no significant difference between the numbers of GnRH neurons of the POA in three estrous phases [P>0.05]. In the luteal phase, percent of GnRH neurons that coexpress GnlH were significantly less than proestrus and estrus phases [P=0.008]. GnlH expression in neurons of POA of ewe in luteal phase is more than follicular phase, but there was no significant difference in expression of GnRH neurons in the POA during the estrous phases. Also during all phases of the estrous cycle, GnRH neurons coexpress GnlH and GnlH neurons coexpress GnRH. These findings showed the direct effect of GnlH neurons on GnRH neurons in POA and indirect control of LH secretion

[Communication between external and rrecurrent laryngeal nerves in human by using dissection method in Shiraz medical school]

The aim of this study was to identify laryngeal nerves anastomosis by dissection methods. Forty human hemi- larynxes were dissected. The recurrent and branches of superior laryngeal nerve [SLN] were dissected under steriomicroscpe and separated from the surrounding tissues. All of the nerves were dissected in order to find the connection branches between laryngeal nerves, especially between the ELN and the RLN. Anastomosis between the external branch of SLN and the RLN appeared as a connecting branch throughout the cricothyroid muscle in 37.5%. Connection between RLN and internal branch of the SLN [Galen anastomosis] was also found in 100% of cases. There are neural connections between external branch of the SLN and RLN in human. These connections can explain unexpected findings after laryngeal nerve damages

[Comparison of marking changes in neural cells detection protocol on superior laryngeal nerve in dogs]

Neuron tracing is a novel method that is used for detecting communications between cells, tracing nervous pathways, and recognizing the nuclei relating to different pathways. One of the most common tracing methods is putting cutting end of nerve inside the tracer solution. This method is so sensitive that improper insertion of the nerve inside a solution or histological preparation, would lead not to observing the tracers. We evaluated methods for observing tracers. 10 adult dogs were assigned into two groups. In the first group, the superior laryngeal nerve was cut and its proximal end, after washing and des-heating, was put inside the horse radish peroxidase [HRP] solution. In the second group, after washing the proximal cutting end of superior laryngeal nerve, we separated tiny vessels supplying the nerve to prevent hemorrhage. Then, by using the needle [gauge 22], 2-3 distal end of nerve sheath was precisely removed and nerve fibers were separated and kept inside the HRP solution. In both groups, nerve end was kept inside the HRP solution for 2 hours. Three to five days later, after perfusion and fixation their head and neck, their pons, medulla oblongata, three upper spinal segments and vagal ganglions were removed, sectioned and prepared histochemically and stained with thionin. The number of labeled cells in the first group was less [2-4 cells per section] than the second group [4-8 cells]. This difference was statistically significant [P<0.05]. This study showed that separating nerve fibers and fixation of nerve end inside the solution increased the absorption of tracer