A new experimental model of stress ulcers employing aggressive behavior in 6-OHDA-treated rats

The Galectin-1 level in serum as a novel marker for stress

Galectin-1(Gal-1), a carbohydrate-binding protein with an affinity for beta-galactoside, is widely expressed in various normal and pathological tissues and it also plays an important role in regulating immune cell homeostasis and tumorigenesis. This study investigated the effects of restraint stress on serum Gal-1 by Western blot analyses and enzyme-linked immunosorbent assays. The Gal-1 levels of the restraint-stress group were significantly higher than those of the control group. However, this increase by stress was not obvious in adolescent rats. The pattern of these changes was similar to that of corticosterone. Furthermore, this Gal-1 increase in the serum was prevented by pre-treatment with a neurotoxin 6-hydroxydopamine (6-OHDA), which destroys the noradrenergic nerve terminals. However, a bilateral adrenalectomy (ADX) had no effect on the Gal-1 increase. These results suggest that Gal-1 is a candidate stress marker protein and that the stress-induced increase of Gal-1 in serum is regulated by the sympathetic nervous system under stress conditions.

Simultaneous determination of noradrenaline and 3-methoxy-4-hydroxyphenylglycol in plasma with high-performance liquid chromatography using electrochemical detection

We herein report the simultaneous determination of the levels of noradrenaline (NA), and 3-methoxy-4-hydroxyphenylglycol (MHPG), a major metabolite of NA. The sample was subjected to a Sep Pak C18 cartridge prior to the NA and MHPG assay by high-performance liquid chromatography with an electrochemical detector. The results correlated well with the established methods. The average percentage of recovery was 91.2 and 98.7% for NA and MHPG, respectively. The intraassay coefficients of variation were 3.7 and 4.6% for NA and MHPG. The interassay coefficients of variation were 3.5 and 7.5% for NA and MHPG, respectively.

Effects of small amygdaloid lesions on pancreatic exocrine secretion

To investigate the role of the amygdala in central regulation of pancreatic exocrine secretion, the effects of electrolytic lesions on pancreatic secretion were studied in rats. Small bilateral electrolytic lesions in amygdaloid body restricted to basolateral, medial and central nuclei were produced. Eight days after the lesions, bile-pancreatic juice was collected following anesthetization with urethane and chloralose. Basal secretion and secretion stimulated by exogenous pancreozymin and secretin were evaluated in terms of amylase output. In the group with basolateral nucleus lesions, both basal and stimulated secretion were significantly increased. After medial nucleus lesions, mean body weight was reduced to 59% of initial, and basal and stimulated secretion were significantly lower than in the control group and also significantly lower than in an unoperated group, whose mean body weight was reduced to the same level as that of the medially lesioned group by restricting daily food intake. After lesions of the central nucleus, basal secretion was significantly increased, while stimulated secretion was not affected. These results indicated that the amygdala is involved in regulating pancreatic exocrine secretion and that its various nuclei exert different effects.

Attack stress and IgE antibody production in rats

The effect of stress on production of immunoglobulin E (IgE) in rats was investigated, the IgE being titrated by passive cutaneous anaphylaxis (PCA) reactions. In rats, exposed to attack by other rats made aggressive by intraventricular injections of 6-OHDA for one hour per day for three consecutive days before the first immunization, there was no difference in the titer of IgE as compared to the control rats, but, in the rats exposed to stress procedure before the second immunization, the production of IgE was significantly suppressed.

Autonomic drug effects and gastric secretion in a new experimental model of stress ulcers in rats

A psychological procedure which does not involve the application of physical stimulation was used to produce gastric ulcers experimentally. Ulceration was induced in rats by exposing the animals to the aggressive attacks of rats treated with 6-hydroxy-dopamine (6-OHDA). Gastric secretion and the effects of autonomic drugs on ulcer formation were investigated. Atropine methylbromide did not significantly inhibit the occurrence of erosions. Phentolamine or hexamethonium bromide significantly inhibited the production of erosions, and combined administration of an anticholinergic agents and alpha-blocking agent led to a complete inhibition, with no notable behavioral change. In case of pylorus ligation, gastric secretion during exposure to attack of 6-OHDA-treated rats was significantly less than that in the controls. We suggest that the sympathetic nervous system plays an important role in the production of gastric erosions, as induced by the methods reported in this study.