Background and objective: Cannabinoids which are active compounds of marijuana show some pharmacological effects similar to the opioids. There are also functional interactions between both cannabinoid and opioid systems. In this study we investigated the role of cannabinoid receptors in central amygdala and its interaction with opioid system.Methods: In the present study, we investigated the effects of intraperitoneal injection of opioid drugs on response-induced by intra-amygdala (intra-Amyg) microinjection of cannabinoid agents in rats, using ELEVATED PLUS-MAZE test of anxiety.Results: Intraperitoneal injection of morphine (3, 6 and 9 mg/kg) increased %OAT and %OAE, but not locomotor activity, showing an anxiolytic response. However, some doses of the opioid receptor antagonist, naloxone reduced %OAT and locomotor activity as well. Intra-Amyg administration of CB1 cannabinoid receptor agonist, ACPA (at the dose of 1.25 and 5 ng/rat) increased %OAT and %OAE but not locomotor activity, thus showing an anxiolytic response, which was increased by morphine (6 mg/kg, i.p.) without any interaction. Naloxone also reduced ACPA effects.Intra-Amyg administration of CB1 cannabinoid receptor antagonist, AM251 (2.5, 25 and 100ng/rat) did not alter %OAT and %OAE but higher doses of drug (25 and 100 ng/rat) reduced locomotor activity. However, the drug in combination of morphine anxiolytic response and with naloxone decreased anxiety. Conclusion: The results may indicate an anxiolytic for CB1 cannabinoid. Our results also showed that opioid system may have interaction with cannabinoid receptor in the amygdale.

Introduction: Based on the extensive application of Peganum harma/a (P.h) seeds in the Asian traditional medicine, we tried to investigate its possible anxiety effect.Method: The effect of P.h. extract inhalation was evaluated in adult male rats using ELEVATED PLUS-MAZE apparatus. The humidity of prepared ethanol extract was 37%. Animals in different groups (n=6) received 2, 4, 6, 12 or 18gr/ml doses of the extract using Nebulizer. harmaline drug (0.13gr/ml) was used as positive control drug.Results: Compared with saline treated group, harmaline as the positive control significantly caused fear in rats as it was shown by increased time spent in closed arm of PLUS-MAZE (p<0.05). Also, ethanol extract of P.h was able to show anxiety effect at doses 6, 12 and 18mg/ml (p<0.05).Conclusion: Our data showed effective anxiety effect of ethanol extract of Peganum harmala. Its effect should be considered in the context of its extensive usage in the men daily life. More studies are required to elucidate its mechanism and site of action.

Background: Salvia leriifolia (Lamiaceae) is indigenous to the east of Iran and some part of Afghanestan. It has many pharmacological effects such as antinociceptive, anti-inflammatory, anti-ischemic, anti-hyperglycemic, hypnotic, muscle relexant, anti-peptic ulcer and anticonvulsant effects.Objective: In this research, the antianxiety effects of aqueous and ethanolic extracts of S. leriifolia Benth. leaves were studied using ELEVATED PLUS MAZE.Method: Nine groups of male mice were used, each of which contained 7-10 animals. Half an hour before anti-anxiety test, the aqueous or ethanolic extracts (100, 200 and 400 mg/kg), diazepam (1 mg/kg) and saline were injected intraperitoneally to mice. The aqueous and ethanolic extracts were dissolved in saline or tween 80, respectively. In anti-anxiety test, the number of entries into open and closed arms by animals was recorded. In motor coordination (Rotarod test) experiment, the extracts were injected 30 or 60 min before the test and in locomotor activity (open field test) experiment, the extracts were injected 60 min before test.Results: In anti - anxiety test, among different doses of the aqueous or ethanolic extracts, only ethanolic extract (in dose of 100 and 200 mg/kg) significantly increased opened arms entrance (p<0.01) and all doses of the ethanolic and aqueous extracts declined closed arms entrance, dose dependently (p<0.001). In Rotarod and open field tests all of doses significantly decreased mice locomotion activity and motor balance (p<0.001).Conclusion: The ethanolic extract of S. leriifolia leaves extract showed anti-anxiety activity and declined locomotion activity and motor coordination in mice.

Introduction: Previous studies have shown that cannabinoidergic system is involved in anxiety.However, there are controversial reports in the experimental studies. The aim of this study is to evaluate the effect of pharmacological stimulation or blocking of CB1 receptors and inhibition of endocannabinoid degradation in anxiety like behavior in ELEVATED PLUS-MAZE (EPM) test in rat.The EPM is one of the most widely used animal models of anxiety.Methods: Male Wistar rats were randomly allocated to ten groups. Different groups of animals intraperitoneally received Win-55212 (0.3, 1 and 5 mg/kg) as CB1 receptor agonist, AM- 251 (0.3, 1 and 5 mg/kg) as CB1 receptor antagonist, URB-597 (0.03, 0.1 and 0.3 mg/kg) as endocannabinoid breakdown inhibitor or saline (as control group) 30 min before submitting into EPM test.Results: The results showed that compared to the control group, Win-55212 (1 and 5 mg/kg) and URB-597 (0.1 and 0.3 mg/kg) significantly increased both of the time and percentage of entries into open arms. AM-251 (1 and 5 mg/kg) significantly decreased the time and percentage of entries into open arms in the EPM test. These substances have no effects on the total distance covered by animals and number of closed arm entries.Discussion: It is concluded that activation of cannabinoid receptor exert anxiolytic effect while blocking of cannabinoid receptor resulted in anxiety behavior. The locomotor activity was not significantly changed by cannabinoid system. It is suggested that potentiation of cannabinoid system may be therapeutic strategy for the anxiety behavior.

Introduction: Traditionally, Peganum harmala seeds (P.h) have been extensively used in the Asia region. We have previously reported the increase of fear behavior by systemic administration of P.h extract. Here, we evaluated the effect of central administration of the extract on the fear behavior.Method: Methanolic extract of the plant's seeds (37% humidity) was prepared for the investigation. ELEVATED PLUSMAZE apparatus was used for evaluating the fear behavior. Adult male rats were categorized in 7 main groups (n=6). 1) Sham control (saline 1 ul/rat, i.c.v) 2) Harmaline treated group (50 ug/rat, i.c.v). 3) Extract treated groups (10, 20, 25, 50, 100 ug/rat i.c.v respectively).Results: All the doses of the P.h Methanolic extract as like as harmaline caused fear behavior (p<0.05). There was no significant difference between the effects of harmaline and the doses of the plant extract.Discussion: Overall, it is possible that the main alkaloid of the P.h (harmaline) is responsible for the increasing of fear behavior. The effect seems to be done trough the central nervous system neurochemical mechanisms.

Background: There are reports in traditional medicine about the effectiveness of Ocimum basilicum (OB) in the treatment of anxiety. The ELEVATED PLUS-MAZE (EPM) has been predominantly used to investigate anxiety levels in rodents.Objectives: The purpose of the present study was to investigate the effectiveness of extract of OB on rat behavior in the EPM test.Materials and Methods: Male Wistar rats weighing 220 - 250 g were used in the present study. Forty rats were divided into 4 groups: three OB groups (25, 50, 100 mg/kg oral administration of OB for 7 days) and a saline control group. One day after the last day of feeding, the animals’ behavior in EPM was videotaped for 10 minutes. Then, their behavior scored for formal indexes of anxiety, such as the total distance covered by animals, the percentage of entries into and the time spent in open and closed arms.Results: The results showed that after oral feeding of OB, the percentage of open arms entry and open arms time in EPM increased in the experimental groups. OB extract has no effect on the total distance covered by animals and number of closed arm entries.Conclusions: Our results demonstrated that the extract of OB could induce anxiolytic effect in rats after 1 week oral administration. The effect of OB was not induced through changes in motor activity. Further investigations are necessary for pharmacological providing of OB and better understanding of its anxiolytic properties and neurobiological mechanisms.