Investigation of Effects of Two Chronic Stress Protocols on Depression-Like Behaviors and Brain Mineral Levels in Female Rats: an Evaluation of 7-Day Immobilization Stress.

We aimed to investigate the effects of two different chronic immobilization stress protocols on depression-related behaviors and brain mineral levels. Adult female Wistar albino rats were divided into 3 groups as follows (n = 10/group): control, immobilization stress-1 (45 min daily for 7 days), and immobilization stress-2 (45 min twice a day for 7 day). Stress-related behavior was evaluated by means of the forced swimming test (FST) and open field test (OFT). Minerals were analyzed using an inductively coupled plasma mass spectrometer. In the FST, swimming and immobility were significantly lower in the immobilization stress-1 and immobilization stress-2 groups. The climbing duration of the immobilization stress-2 group was higher than the control group. In the OFT, percentage of time spent in the central area was significantly lower in the immobilization stress-1 and immobilization stress-2 groups. Values of latency to center area, rearing, and grooming did not significantly differ between groups. In the immobilization stress-1 group, zinc was lower, and iron, copper, and manganese were higher than the control group. In the immobilization stress-2 group, copper and manganese were higher, and phosphate was lower than the control group. Our results showed that depression-related behaviors were more dominant in the immobilization stress-1 group. A decrease in the brain zinc level was valid only for the immobilization stress-1 group. These results point to the role of low brain zinc levels in the pathophysiology of depression.

Analgesic effects of mad honey (grayanotoxin) in mice models of acute pain and painful diabetic neuropathy.

OBJECTIVES: The aim of this experimental study was to investigate the effects of mad honey (grayanotoxin, GTX), used in complementary medicine for a variety of purposes besides being food, on pain thresholds in normal mice as model for acute pain and diabetic mouse as model for neuropathic pain. METHODS: Hind paw withdrawal pain threshold to thermal stimulus was measured with a plantar analgesia meter in a mice model using healthy intact animals for acute pain and streptozotocin-induced diabetic animals for chronic neuropathic pain. Time and dose-dependent effects of intraperitoneally (i.p.) administered GTX were investigated in both acute and neuropathic pain. RESULTS: In the acute pain model, administration of GTX caused a dose- and time-dependent marked increase in the pain latency values. In diabetic mice, which had markedly increased threshold to pain, GTX (0.1 mg/kg, i.p.) restored the mean pain latencies by decreasing from the pre-GTX treatment values of 3.2 ± 0.6 to 3.0 ± 0.9s at 10 min, 3.2 ± 0.6s at 20 min, 3.4 ± 0.6s at 30 min, 2.6 ± 0.5s at 60 min and 2.4 ± 0.6s (p < 0.05) at 100 min. CONCLUSION: The results from this experimental study indicate that GTX exhibits significant analgesic activity and has potential benefits against painful diabetic neuropathy. This is compatible with the widespread use of GTX containing mad honey for alleviating pain. Further studies involving long-term applications are needed for a more decisive conclusion regarding the usefulness of GTX as an analgesic, especially in the treatment of painful neuropathy.