The action of orexin A on passive avoidance learning. Involvement of transmitters

Formaldehyde, as a frequently used compound in many applications, crosses the blood-brain barrier and leads to hippocampal cell death and memory impairment. This study investigates the effects of ethanolic extract of Matricaria chamomilla (MC) on passive avoidance learning induced by damaged hippocampal cells and evaluates the antioxidant traits of MC. The male Wistar rats were divided into six (6 in each) groups: control (10 mg/kg normal saline), 200 (200 mg/kg MC extract), 500 (500 mg/kg MC extract), F (10 mg/kg formaldehyde), F200 (10 mg/kg formaldehyde and 200 mg/kg MC extract), and F500 (10 mg/kg formaldehyde and 500 mg/kg MC extract). Shuttle box assay was used for evaluation of passive avoidance learning. The apoptosis rate of hippocampal tissue, malondialdehyde (MDA) free radicals, and total antioxidant capacity was evaluated to determine the positive effect of the ethanolic extract of MC. We found that the ethanolic extract of MC reduced the cell death, time spent in a dark room, and MDA free radicals in the hippocampus, leading to increased total antioxidant capacity in this region. In conclusion, the ethanolic extract of MC could ameliorate formaldehyde-induced memory damage through decreasing cell death and MDA activity of the hippocampal region and increasing total antioxidant capacity.

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Effect of a hydro-alcoholic extract of Melissa officinalis on passive avoidance learning and memory

Journal of Herbmed Pharmacology ◽

10.15171/jhp.2019.19 ◽

2019 ◽

Vol 8 (2) ◽

pp. 120-125 ◽

Cited By ~ 1

Author(s):

Zahra Dehbani ◽

Alireza Komaki ◽

Farshid Etaee ◽

Siamak Shahidi ◽

Masoumeh Taheri ◽

...

Keyword(s):

Passive Avoidance ◽

Learning And Memory ◽

Avoidance Learning ◽

Saline Group ◽

Passive Avoidance Learning ◽

Male Rats ◽

Control Group ◽

Alcoholic Extract ◽

Melissa Officinalis ◽

Significant Difference

Introduction: Melissa officinalis (MO) or lemon balm is traditionally used as a sedative and anti-spasm herbal medicine. There is also evidence that this plant has effects on learning and memory. This study examined the effect of a hydro-alcoholic extract of MO on passive avoidance learning (PAL) and memory in male rats. Methods: A total of 40 adult male Wistar rats were randomly distributed into four groups (200 to 220 g; n = 10 per group); three dose groups (50, 100, and 200 mg/kg of the hydro-alcoholic extract of MO) and vehicle control (saline) group. Saline or doses of extract were administered daily for 14 days by oral gavage. The rats were trained to enter the shuttle box to record their behavior in the PAL task. A retrieval test was performed 24 hours following training. Results: A significant difference was seen in performance among MO groups and the control. MO administered animals had a decreased number of acquisition trials (P < 0.05). In the retention task, MO administered animals had an increased step-through latency (SLT) (P < 0.01), and a decreased latency in the dark compartment (P < 0.001) compared to the control group. Conclusion: The results of the study show that MO can improve learning and memory in the PAL task. Further investigation is needed to enhance our understanding of the neurobiological mechanisms of the MO extract and its effects on learning and memory.

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