Effects of Melissa officinalis on ethanol state-dependent learning in nicotine- treated mice

Abstract

Objectives: Melissa officinalis has antioxidant and antidepressant effects. Besides, it could be good in learning and memory due to its terpenoides. The possible role of Melissa officinalis on ethanol state-dependent learning was studied in adult nicotine-treated male mice.Methods: As a model of memory, a single-trial step-down passive avoidance task was used. In this project, ethanol (0.25, 1 g/kg) and nicotine (0.01, 0.1 mg/ kg) was administrated 30 minutes before training and testing. Melissa officinalis extract (25 mg/kg) was administrated 30 minutes before testing, and then step down latency (SDL) was measured. Key finding:The obtained results showed that administration of ethanol (0.25, 1 g/kg) and nicotine (0.1 mg/ kg) before training could decrease SDL, whereas, nicotine (0.01mg/kg) increased SDL. Conclusion:Pre testing administration of ethanol (1 g/kg), nicotine (0.1 mg/kg) and Melissa officinalis extract (25 mg/kg) could ameliorate decreasing effects of pre training ethanol (0.25, 1 g/kg) and nicotine (0.1 mg/kg) on SDL. Keywords: Mellisa Officinalis Extract (Varangboo); Ethanol State DependentLearning; Nicotine-Treated Mice Institute of Iran, housed in groups of six in stainless-steel cages, and given food and water ad libitum under a standard 12 h light/12 h dark cycle. All training and test sessions were performed in a glass room where only the wooden platform was placed in (standard conditions) middle of the box. Effects of Melissa Officinalis on Ethanol State-Dependent Learning in Nicotine-TreatedFour groups of animals received saline 30 minutes before training and saline, nicotine (0.01, 0.1 mg/kg), ethanol (1, 0.25 g/ kg) and Melissa officinalis extract (25 mg/kg) before testing. Other groups received ethanol( 0.25 g/kg) 30 minutes before training and ethanol (0.25g/kg) before testing, two groups, 30 minutes before training received ethanol (0.25, 1 g/kg) and nicotine (0.1, 0.01 mg/kg). These groups also received saline before testing. Three groups received ethanol (0.25 g/kg), nicotine (0.1 mg/kg) and both of them 30 minutes before training and Melissa officinalis extract (25 mg/kg) before testing. Behavioral proceduresTraining: In the training day, each mice received nicotine or ethanol intra peritoneally (IP) and then 30 min after injection each mice was gently placed on the platform. Five seconds 0.4-mA shock was applied to the grid after which animals were immediately withdrawn from the training apparatus. This training procedure was carried out.Retention test: Twenty-four hours after training, step-down latency was measured 30 min after the last injection. Each mice was gently placed on the platform, without any shock. The stepdown latency (SDL) was taken as a measure of retention. Task:The wood escape platform used for the spatial task at the middle of the glassy box. An electric shock (0.4 mA, 5 s) was delivered to the grid floor by an isolated stimulator. Plant material and extraction procedureThe total plant extract was obtained by extraction of dried and milled plant leaves w...

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“…The role ofMelissa officinalis (25 mg/kg) on ethanol state-dependent learning was studied in adult nicotine-treated male mice. Melissa officinalis extract (25 mg/kg) ameliorated the decreasing effects of pre training ethanol (0.25, 1 g/kg) and nicotine (0.1 mg/kg) on step down latency (SDL) [156].…”

“…The total extract of Nigella sativa and its separated fractions was studied in vitro. The total extract of Nigella sativa (10, 100, 250, 500, 750 and 1000 μg/ml) and all the separated fractions inhibited AChE enzyme in a concentration-dependent manner (156). Nigella sativa increased 5-HT levels in brain and improved learning memory in rats [167].…”