Previous research has suggested a role for corticotropin-releasing factor (CRF) in the anxiogenic effects of stressful stimuli and ethanol withdrawal. This hypothesis was explored in a series of experiments using intracranial microdialysis to monitor CRF-like immunoreactivity (CRF-IR) in the extracellular compartment of the rat amygdala. The synaptic origin of CRF-IR release in the amygdala was determined in vitro by assessing the Ca2+ dependency of 4-aminopyridine stimulated CRF-IR release from tissue preparations of rat amygdala. In vivo experiments were performed in awake rats after the placement of microdialysis probes in the amygdala. In the first experiment, transient restraint stress (20 min) produced an increase of CRF-IR release (basal levels, 1.19 +/- 0.15 fmol/50 microliters; stress levels, 4.54 +/- 1.33 fmol/50 microliters; p < 0.05) that returned to basal values within 1 hr. When 4-aminopyridine (5 mM) was added to the perfusion medium, it consistently increased CRF-IR release (4.83 +/- 0.92 fmol/50 microliters, p < 0.05). In the second experiment, CRF-IR release was measured during ethanol withdrawal in rats previously maintained for 2–3 weeks on a liquid diet containing ethanol (8.5%). Basal CRF-IR levels were 2.10 +/- 0.43 fmol/50 microliters in ethanol exposed rats and 1.30 +/- 0.19 fmol/50 microliters in control rats. During withdrawal, a progressive increase of CRF-IR levels over time was observed, reaching peak values at 10–12 hr after the onset of withdrawal (10.65 +/- 0.49 fmol/50 microliters vs 1.15 +/- 0.30 fmol/50 microliters of control rats, p < 0.01).

SummaryBackground: Glaucoma is a highly prevalent eye disease related to optic nerve lesions and visual field defects. Primary Open-Angle Glaucoma (POAG) is a type of glaucoma that occurs frequently with unknown etiology. In this study, we investigated the serum levels of selenium, selenoprotein P1, glutathione, hemolysate glutathione peroxidase1 (GPx1) activity and aqueous humour selenium in POAG patients. Methods: Ninety sex-and age-matched subjects (POAG patients; n=45 and, controls; n=45) with the controlled confounders (smoking, hypertension and alcohol beverages) were recruited on clinical histories and exams. The serum and aqueous humour selenium levels were measured using GFAAS technique. The serum selenoprotein P1 level was assayed with the ELISA method. The hemolysate GPx1 activity and serum reduced glutathione level were also measured using known colorimetric techniques. Results: The serum selenium (P=0.01) and selenoprotein P1 (P<0.001) levels were significantly high in POAG patients. Furthermore, the aqueous humour selenium level was significantly high among patients as compared to controls (64.68±13.07 vs. 58.36±13.76 ng/mL, P=0.02). The results did not show a significant difference (P=0.36) in the hemolysate GPx1 activity between the groups. The cutoff points for intraocular pressure (IOP) and serum selenoprotein P1 parameters were estimated to be 39 mmHg (sensitivity 97.5%; 1-specificity 6.5%) and 188 mg/mL (sensitivity 93.5%; 1-specificity 14%), respectively.