Compression of The Sciatic Nerve May not Contribute to Ipsilateral Hyperalgesia Development in Ovariectomized Female Rats!

OBJECTIVE: von Frey Filament (vFF) is an aesthesiometer to measure paw withdrawal thresholds. Our aim was to validate the manually von Frey test technique for assessing neuropathic pain behavioral signs in a sciatic nerve ligation model. MATERIALS AND METHODS: In this experimental study, peripheral neuropathic pain associated with sciatic nerve chronic ligation (SN-CL) was induced. Filaments used against posterior pad mid-plantar region using a simplified up-down method (SUDO). In addition to baseline withdrawal thresholds, the behavioral test was repeated after surgery thrice more with an interval of ten days. vFF (2 to 26 g) were used in ascending order for hyperalgesia assessment. RESULTS: In SN-CL rats, the results validate a loss of pain sensation, resulted in, long-lasting ipsilateral allodynia with the development of contralateral allodynia later and an extraterritorial development of neuropathic signs. Variability for the development of ipsilateral and contralateral allodynia over time was noted in sham (SH) control rats. SN-CL group showed a contralateral hyperalgesia development just at the 16th-day after surgery with an absence of ipsilateral hyperalgesia development at the different days of paw withdrawal thresholds measurements. CONCLUSION: Manually vFF test technique was successfully used for assessing neuropathic pain behavioral signs in sciatic a nerve ligation model with the absence of ipsilateral hyperalgesia development.

[Ketoconazole antagonizes the immune and gonadotropic systems in the forced swimming test in male Wistar rats]. / Le kétoconazole antagonise les effets immuno-gonadotropes au test de la nage forcée chez le rat mâle Wistar.

Disturbances in the activity of the corticotropic axis and immune system have been widely reported to be linked to the development of depression. The aim of this study was to explore the effects of ketoconazole, an imidazole derivative that inhibits gonadal and adrenal steroidogenesis, on changes in the total leukocyte count and the percentages of leukocyte subpopulations during the Porsolt forced swimming test (commonly used to measure the efficiency of antidepressants) in rats. Catheters were implanted in the carotid under general anesthesia, and blood samples (0.2 mL) were taken at 15 min intervals. Animals were allowed to move freely throughout the experiments. The levels of anxiety and locomotor activity were measured using the elevated plus-maze and open-field tests. Forced swimming induced changes in both the testosteronemia and the immune system, and these changes were inhibited by treatment with ketoconazole. An improvement (anxiolytic and antidepressant effects) in the behavioral response (elevated plus maze, forced swim) was also observed. These results suggest that the relationship between behavioral and physiological responses is multifactorial and that corticosterone plays a major role in the pathogenesis of psychiatric disorders.