Experimental Study of the Analgesic Effect of the Antidepressant Escitalopram.

BACKGROUND: Antidepressants have been found to possess antinociceptive and analgesic properties and are prescribed in the treatment of chronic pain. AIM: To evaluate the antinociceptive properties of escitalopram after a single administration. MATERIALS AND METHODS: Forty Wistar rats were used in the study. They were divided into 5 groups (n=8) treated with saline solution (control group), metamizole (150 mg/kg b.w.), escitalopram (5, 10 and 20 mg/kg b.w.) intraperitoneally. The nociceptive tests we used employed thermal (hot plate and plantar test), mechanical (analgesimeter) and chemical (formalin test) stimuli. Criteria for analgesic effect were increased latency in hot plate, plantar test, analgesimeter and decreased paw licking time in formalin test. RESULTS: The reference analgesic metamizole showed significant analgesic effect in all tests excluding the first phase with formalin. Escitalopram in doses of 5 and 20 mg/kg b.w. increased paw withdrawal latency in analgesimeter at 2 hours compared to control. Escitalopram in a dose of 5 mg/kg b.w. increased the duration of the stay on the hot plate at 1 hour, while doses of 10 and 20 mg/kg b.w. significantly increased this indicator at 1 and 3 hours in comparison to the saline treated group. In the plantar test, escitalopram in all used doses significantly increased the nociceptive response latency compared to control. A dose of 5 mg/kg b.w. decreased hind paw licking time during phase 1 of the formalin test, whereas doses of 10 and 20 mg/kg b.w. decreased phase 2 licking time compared to the control group. CONCLUSION: The antidepressant escitalopram has analgesic properties but they are not dose- or time-dependent.

Antidepressant Effect and Recognition Memory Improvement of Two Novel Plant Extract Combinations - Antistress I and Anti-stress II on Rats Subjected to a Model of Mild Chronic Stress.

BACKGROUND: Chronic stress is one of the main factors which lead to depression - a psychiatric disorder affecting millions of people and predicted to be the second ranked cause of premature death in 2020. Depression is often associated with cognitive disturbances and memory deficit. Plant based therapy could be effective in the treatment of mild to moderate depression due to its low level of adverse reaction, its good tolerability and compliance. MATERIALS AND METHODS: 72 male Wistar rats, divided in 9 groups were given orally for 8 weeks two combinations of dry plant extracts - Antistress I and Antistress II and five individual dry extracts obtained from Serratula coronata, Hypericum perforatum, Valeriana officinalis, Crataegus monogyna and Melissa officinalis. The animals were exposed to a chronic unpredictable mild stress for 8 weeks. The depression-like symptoms were evaluated with Forced swim test while the assessment of the memory deficit was performed with Novel object recognition test. RESULTS: Antistress II demonstrates antidepressant effect while Antistress I doesn't improve the depressive-like symptoms. The individual extracts of Hypericum perforatum and Valeriana officinalis also possess antidepressant properties. Antistress II improves the cognition as well as the individual extracts of Hypericum perforatum, Valeriana officinalis and especially Serratula coronata. Dry extract from Serratula tend to have the best effect regarding the recognition memory. The effect of Antistress I on memory deficit is negligible. CONCLUSIONS: Antistress II possesses antidepressant effect and improves the recognition memory while Antistress I doesn't demonstrate any of the above-described effects.

Effect of atorvastatin and rosuvastatin on learning and memory in rats with diazepam-induced amnesia.

UNLABELLED: During the past decade, evidence has emerged that statins have neuroprotective effects. AIM: The aim of this study was to investigate the effects of atorvastatin and rosuvastatin on learning and memory in rats with diazepam-induced amnesia. MATERIAL AND METHODS: Experiments were carried out on 48 white male Wistar rats, divided into 6 groups, each of 8 rats. The experimental animals were treated per os for 14 days with atorvastatin and rosuvastatin in doses of 10 mg/kg and 20 mg/kg body weight, respectively. To induce amnesia diazepam was administered intraperitoneally in a dose of 2.5 mg/kg bw. Cognitive skills of the animals were examined after the induction of amnesia with active avoidance test using autonomic reflex conditioner (shuttle box) and passive avoidance tests (step-through and step down) (Ugo Basile, Italy). The following parameters were assessed: number of conditioned responses (avoidances), number of unconditioned responses (escapes) and number of intertrial crossings in the active avoidance test; latency of reactions was measured in the passive avoidance tests. RESULTS: We found a significant increase of conditioned responses in atorvastatin treated animals (in a dose of 10 mg/kg bw) in active avoidance training. In the animals treated with rosuvastatin in both doses there was a statistically significant increase of unconditioned responses. In the step-through passive avoidance test there was significant improvement of short-term and long-term memory following administration of atorvastatin (10 mg/kg bw). Rosuvastatin (10 mg/kg bw) preserves long-term memory. In the step-down passive avoidance test, atorvastatin (10 mg/kg bw) and rosuvastatin (10 mg/kg bw and 20 mg/kg bw) preserve long-term memory. CONCLUSIONS: Atorvastatin (10 mg/kg bw) and rosuvastatin (10 mg/kg and 20 mg/kg bw) improve cognitive functions in rats with diazepam-induced amnesia and preserve long-term memory.