No abstract

This study aimed to assess the effects of examination stress on salivary cortisol, immunoglobulin A (IgA), and chromogranin A (CgA) in nursing students. Saliva samples were collected from 15 healthy females before and immediately after the one-hour examination, and two hours after the examination. Salivary cortisol, IgA, and CgA concentrations were determined by enzyme-linked immunosorbent assay. Both IgA and CgA concentrations statistically increased immediately after the examination (P < 0.05) and decreased two hours after the examination. No significant differences were observed between before and after the examination in the salivary cortisol concentration. These findings suggest that the acute stress due to the examination is associated with raised salivary IgA and CgA, but not cortisol.

No abstract

Cytoarchitecture and fiber connections of the nucleus isthmi in a teleost (Nauodon modestus) were studied by means of Nissl, Bodian, toluidine blue, Golgi, and Fink-Heimer methods. Synaptic terminals were classified by the ultrastructural characteristics, and their origins were determined by electron microscopic degeneration experiments.The nucleus isthmi is composed of an outer cellular area or shell and an inner noncellular area or core. The shell covers anterior, dorsal, and ventral aspects of the core. The cell bodies in the shell are oval (15 x 20 pm) with an anteroposterior long axis, and have many somatic spines. Spines are also seen on the initial segment of the axon. Primary dendrites extend posteromedially and branch out in the core. The core contains thin and thick myelinated fibers, which originate in the optic tectun and in the nucleus pretectalis, respectively.At least two types of axon terminal were distinguished in the nucleus isthmi: S type, containing spherical vesicles, and F type, containing flattened vesicles. S terminals are derived from thin myelinated fibers and are only seen in the core where they form asymmetric synapses with dendrites.Frequently a portion of the S terminal membrane near the usual synaptic cleft is in close apposition with the membrane of an adjacent small dendrite or spine. F terminals, which derived from thick myelinated fibers, make symmetric synaptic contacts with both cell bodies in the shell and dendrites in the core. S terminals degenerate after ipsilateral ablation of the optic tectum, whereas F terminals degenerate after destruction of the nucleus pretectalis.The nucleus isthmi receives a substantial projection from the optic tectum in teleosts (Schroeder, '74 , '76). The nucleus isthmi, in turn, mainly projects to the optic tectum in these vertebrates. From the reciprocal fiber connections, the nucleus isthmi is thought to be homologous to the parabigeminal nucleus of mammals (see Gruberg and Udin, '78). It is also of particular interest that these reciprocal connections are topographically arranged. 300Teleostean isthmic afferent neurons were first identified in Navodon modestus by means of the retrograde horseradish peroxidase (HRP) method (It0 et al., '81). The large pyriform neurons described by Vanegas et al. ('74) were labeled in the optic tectum. The cell body of this type of neuron lies in the upper part of the stratum periventriculare. These neurons are quite similar to those in the pigeon (Hunt et al., '77). Somewhat unexpectedly, neurons of the nucleus pretectalis of Schnitzlein ('62) were also labeled. The nucleus pretectalis receives fibers from the optic tectum but not from the retina (Sakamoto et al., '81). It is obvious from these data that the nucleus isthmi in teleosts receives tectal input via two different pathways: direct tecto-isthmic and indirect tecto-pretecto-isthmic pathways. The indirect pathway has not been demonstrated in other classes of vertebrates. Neurons which constitute the teleostean nucleus pretectalis, therefore,...

Participation of nitric oxide in the electrical field stimulation-induced nonadrenergic, noncholinergic (NANC) relaxation in various intestinal regions was studied in 2- to 50-week-old Wistar rats. In the jejunum of 2-week-old rats, the extent of the nitric oxide-mediated component of the relaxation of longitudinal muscle was approximately 60-70%, whereas the component was 40-50% in 4-week-old rats and was absent in 8- and 50-week-old rats. Thus, nitric oxide seems to be the most important mediator at young ages but its significance is lost with age. The same tendency as that in the jejunum was also shown in longitudinal muscle of the ileum, proximal and distal colon, and rectum. The tendency was also shown in the circular muscle of the rectum. Sensitivity of the longitudinal muscle of the jejunum and proximal colon to exogenously added nitric oxide was high in younger rats. Immunoreactive structures for nitric oxide synthase were observed in the circular muscle layer of the rectum. The population of the structures was denser in 4-week-old than that in 50-week-old. The results suggest that NANC relaxation in every region of the intestine at 2-week-old is almost solely mediated by nitric oxide, and its significance as an inhibitory mediator gradually or rapidly decreases with age.