Investigou-se a participação do cortisol na osmoregulação de peixe-rei Odontesthes bonariensis, em diferentes salinidades, em peixes adultos injetados com 0,7mg hidrocortisona por 100g de peso corporal, e transferidos para 0, 5 e 20ppt de NaCl. No inicio do experimento (0h), o cortisol encontrado no plasma foi de 566ng/ml, aumentando para 1250ng/ml em 3h em peixes injetados com cortisol. A concentração de cortisol foi influenciada não somente pelo tratamento, mas também pelo tempo, sendo maior 3h após a inoculação, comparada à 24h. A salinidade, o tempo de exposição e a interação desses dois fatores, mas não o tratamento com o cortisol, afetaram significativamente a osmolaridade e a concentração dos íons Cl- e Na+ do plasma. Este estudo mostrou que, o cortisol exógeno não influi significativamente na regulação da osmolaridade e da concentração de íons Na+ e Cl- no plasma em peixe-rei.

The role of cortisol on the osmoregulation of pejerrey Odontesthes bonariensis at different salinities was investigated in adult fish injected with 0.7mg hydrocortisone per 100g body weight of fish, and transferred to 0, 5 and 20ppt of NaCl. Blood cortisol was 566ng/ml at the beginning of the experiment (0h) but surged to 1250ng/ml within 3h in cortisol-injected fish. Cortisol levels were influenced not only by treatment but also by time, being higher at 3h compared to 24h. Salinity level, time of exposure and their interaction, but not cortisol treatment, significantly affected plasma osmolality and the concentration of ions Cl- and Na+. This study showed that exogenous cortisol does not seem to play a significant role on the regulation of plasma osmolality and concentration of individual ions in pejerrey.

The purpose of this paper was to study the sensory myelinated and unmyelinated nerve fibers found in the subepithelial lamina propria of tongue mucosa of aging rats. It was used the silver impregnation, transmission electron microscopy methods and morphometric measurements. The results revealed that subepithelial nerve fiber bundles of the anterior, medium and posterior regions of tongue were arise from deep muscular layer of tongue. The nerve fiber bundles were verified inside of the connective tissue of lamina propria. These nerve fibers branched several times and into the connective tissue papillae they form a single or ramified sensory nerve endings. The fungiform and vallate papillae contain numerous nerve terminals. The fine structure demonstrated that in the axoplasm were noted the presence of neurofilaments, mitochondria and microtubules. Although the morphometric data of myelinated fibers showed that about 44% having larger diameter between 3 to 4 µm and the mean value was 4.5 µm. The largest diameter was 12 µm and the smaller was 1.4 um. The smallest diameter ranges from 1 to 3 µm, being that the mean value was 2.33 µm. Concerning to the thickness of myelin sheets were revealed the values ranging from 0.2 to 0.8 µm being that the 90% present the values around 0.5 µm. The unmyelinated fibers showed the largest diameter (62%) varying from 0.25 to 0.75 µm. The mean value was 0.6 µm being the maximum value was 3.17 µm and the minimum was 0.2 µm. The smallest diameter was obtained in 44% of unmyelinated fibers which the diameter ranges from 0.2 to 0.4 µm.Then maximum value obtained was 1 µm and the minimum was 0.12 µm

El objetivo de esta investigación fue estudiar las fibras sensitivas mielinizadas y amielínicas localizadas en la lámina propia subepitelial de la mucosa lingual de ratas. Se usó el método de impregnación argéntica, microscopía MET y mediciones morfométricas. Los resultados revelaron que los fascículos de fibras subepiteliales de las regiones anterior, media y posterior de la lengua provenían de su capa muscular profunda. Los grupos de fibras fueron localizados dentro del tejido conectivo de la lámina propia. Estas fibras nerviosas se ramificaron varias veces y en el tejido conectivo de las papilas formaron terminaciones simples o ramificados. Las papilas fungiformes y valadas contenían numerosas terminaciones nerviosas. La ultraestructura demostró en el axoplasma la presencia de neurofilamentos, mitocondrias y microtúbulos; aunque los registros morfométricos de las fibras mielinizadas mostraron que alrededor del 44% tenían un diámetro entre 3 y 4 µm, el valor promedio fue de 4.5 µm. El diámetro mayor fue de 12 µm y el menor de 1.4 um. Los rangos de menores diámetros fueron de 1 a 3 µm, siendo el promedio de 2.33 µm. En relación al espesor de las vainas de mielina, los valores obtenidos fueron de 0.2 a 0.8 um siendo el valor promedio de alrededor de 0,5 µm, en el 90% de ellas. En las fibras amielínicas los mayores diámetros (62%) variaron entre 0.25 y 0.75 µm. El valor promedio fue de 0.6 µm, siendo el valor máximo 3.17 µm y el mínimo 0.2 µm. El menor diámetro fue obtenido en 44% de las fibras amielínicas y los rangos variaron entre 0.2 y 0.4 µm. El valor máximo obtenido fue de 1 µm y el mínimo 0.12 µm