Stimulation and transient inactivation of ventral tegmental area modify reinstatement of acquisition phase of morphine-induced conditioned place preference in male rats.

For processing the development of psychological dependency, opioid reinforcement, and opiate-related associative reward, learning, and memory in the brain, the ventral tegmental area (VTA) is considered the key zone. As the responsible region for the morphine role in conditioned place preference (CPP), this area has an important role. So, the present research was conducted to investigate the effects of different intensities of electrical stimulation on VTA utilizing CPP, with two morphine doses. Reversible inactivation of VTA was performed via bilateral microinjection of Lidocaine into this area with two implanted separate cannulas. Our findings indicated that 5 mg/kg morphine-induced CPP was suppressed by 150 µA VTA electrical stimulation. The results also showed that bilateral Intra-VTA administration of Lidocaine significantly decreased the 5 mg/kg morphine-induced CPP acquisition phase in comparison with their respective sham group, which reversed in the reinstatement test. It should be concluded that these findings are important for the detection of mesolimbic nervous system ties and could help to find new ways to attenuate the rewarding action of morphine.

Hydroalcoholic Tarooneh Extract (Spathe of Phoenix Dactylifera) Increased Sedative-hypnotic Effects and Modulated Electroencephalography Brain Waves in Anesthetized Rats.

BACKGROUND: Spathe of phoenix dactylifera is hard-covering envelope of date palm which is mentioned as a nerve relief in ancient medicine books. In this experiment, three extract doses used in sleeping time, sedative efficacy, and electroencephalography (EEG) protocol to show different aspects of extract effects on sleep. MATERIALS AND METHODS: In three sleeping time, anesthesia time and EEG experiment protocols test group containing three extract doses (62.5, 125, and 250 mg/kg) were compared with saline control group, and in sleeping time experiment control group contained intact, midazolam, and saline group to detail more in behavioral Angel method. RESULTS: Three extract doses increased sleeping time when compared with saline control group (P < 0.05). In evaluated sedative efficacy, two 125 and 250 mg/kg doses increased anesthesia and showed sedative effect (P < 0.05). In EEG experiment, dose 125 mg/kg increased delta waves and decreased high-frequency waves of alpha and beta. In addition, there were significant decreases in alpha waves of 62.5 and 250 mg/kg doses. CONCLUSION: Although all three doses increased sleeping time, dose 125 mg/kg is more efficient for deep and relaxing sleep and suits more for related researches.

Effects of lactulose and silymarin on liver enzymes in cirrhotic rats.

Silymarin, a mixture of antihepatotoxic flavonolignans used in the treatment of liver diseases, and lactulose, a nonabsorbable synthetic disaccharide, were investigated to analyze their probable synergic and healing effects in a hepatic cirrhotic rat model. Liver damage was induced by the administration and subsequent withdrawal of thioacetamide. The significant decrease in liver enzymes and malondialdehyde levels confirmed the curative effects of silymarin and lactulose. In the silymarin + lactulose group, liver enzyme and malondialdehyde levels were significantly reduced compared with those in the thioacetamide group. All treatments led to liver regeneration and triggered enhanced regeneration. Silymarin and lactulose alone or in combination have potent curative effects and reduce thioacetamide-induced liver damage.

The effect of hydro-alcoholic of Phoenix Dactylifera extract on sleep and EEG in rat.

OBJECTIVE: Hard envelope of date palm pollen is used as a sedative and calmative compounds in Iranian traditional medicine. We tried to study the effects of Phoenix dactylifera (Tarooneh) extract on sleep time and Brian waves. MATERIALS AND METHODS: Rats were divided into control and test groups in sleep experiment. Control groups included intact group (without any injection), negative control group (saline) and positive control group (midazolam 0.1 mg/kg). Test groups received three doses of Tarooneh extract (62.5, 125 and 250 mg/kg). Rat were placed in sleep physiograph system and recording started 20 min after 2-hr calming down. Four parameters including sleep time, awakening, most activity period and main sleep time interval were measured. In EEG experiment electrodes were placed under the cranium for EEG recording and waves were compared with their baselines. RESULTS: All doses of the extract increased sleeping time (p< 0.05) but just the dose of 250 mg/kg (p<0.05) and midazolam (p< 0.001) decreased the awakening time. EEG results showed that the dose of 125 mg/kg increased the low frequency waves (p< 0.05) and the dose of 250 mg/kg decreased high frequency waves of alpha and beta (p< 0.05). CONCLUSION: Due to these effect on sleeping time and EEG, Tarooneh extract consumption can be useful as a sedative agent in Iranian traditional medicine. According to this study, the doses of 125 and 250 mg/kg of the extract would be the appropriate doses to be further studied.

The effects of NBM- lesion on synaptic plasticity in rats.

The nucleus basalis magnocellularis (NBM) is a major source of cholinergic projections to the neocortex that is vulnerable to degeneration in Alzheimer's disease. Despite numerous anatomical, pharmacological, behavioral, and physiological investigations of NBM, there is no in vivo study of its effects on short- or long-term synaptic plasticity. Hence, this study was devoted to the assessment of the effects of bilateral lesion of the NBM on synaptic plasticity in the dentate gyrus of the hippocampus using electrophysiological techniques. For this purpose, twenty-five male Wistar rats were randomly allocated into the three Control, Sham, and NBM-lesioned groups. Lesion was made via bilateral injections of 5µg/µl ibotenic acid. After twenty-one days, the input-output functions, paired-pulse facilitation/inhibition, and long-term potentiation (LTP) were evaluated in the dentate gyrus while the perforant pathway was stimulated. NBM lesion was found to attenuate the basal synaptic responsiveness, paired-pulse responses, and LTP in the rats' dentate gyrus, indicating that lesions of this cholinergic nucleus affects both short- and long-term neural plasticity in the dentate gyrus although NBM does not send direct cholinergic projections to the hippocampus.

The effect of continuous ELF-MFs on the level of 5-HIAA in the raphe nucleus of the rat.

The aim of this study was to investigate the effect of continuous extremely low frequency magnetic fields (ELF-MFs) with a frequency of 10 Hz and an intensity of 690-720 µT on the level of 5-hydroxyindolacetic acid (5-HIAA) in adult male Wistar rats. A total of 24 adult Wistar male rats were used, and after exposure with an ELF-MF for 15 successive days, all rats in each test were anesthetized with chloral hydrate. Then, they were placed in a stereotaxic frame for surgery and a microdialysis process. Dialysate samples were analyzed to measure the amount of 5-HIAA by high performance liquid chromatography (HPLC) using electrochemical detection. Results showed that ELF-MF exposure for 15 days, 1 h daily, was not effective in altering the level of 5-HIAA. However, ELF-MF exposure for 15 days, 3 h daily, decreased the level of the 5-HIAA in the raphe nucleus. It can be concluded that ELF-MFs affect the serotonergic system and may be used to treat nervous system diseases. This study is an initial step towards helping cure depression using ELF-MFs.

The effect of red grape juice on Alzheimer's disease in rats.

BACKGROUND: Alzheimer's disease is a neurodegenerative disease appearing as a result of free radicals and oxidative stress. Antioxidants agents boost memory and control Alzheimer's disease. Since red grape juice contains antioxidant agents, its effects on speed of learning and improvement of memory was studied in Alzheimer's rats. MATERIALS AND METHODS: Alzheimer's model was induced by bilateral infusion of streptozocine into lateral ventricles of brain of male rats. Rats drank 10% red grape juice for 21 days. Passive avoidance learning test was used for measuring memory and learning in rats. RESULTS: Our results showed that learning and memory in STZ-group decreased significantly compared to Sham group. However, intake of red grape juice increased speed of learning and improvement of memory in Alzheimer's rats. CONCLUSIONS: Our results suggest that there are active ingredients in red grape juice, which probably have therapeutic and preventive effects on cognitive impairments in Alzheimer's disease.