WIN55,212-2 impairs non-associative recognition and spatial memory in rats via CB1 receptor stimulation.

Endogenous and exogenous cannabinoids modulate learning and memory primarily via the cannabinoid type 1 receptor (CB1R). A variety of experimental procedures has focused on the role of CB1R in various aspects of learning and memory processes. However, the picture still remains unclear as there is a lack of information on the effects of relatively low doses of CB1R agonists in relation to their effects on locomotion. The present study sought to investigate CB1R activation, using a range of relatively low doses of the CB1R agonist WIN55,212-2, on multiple aspects of learning and memory in rats. For this purpose, non-associative learning was examined using the habituation of locomotion paradigm, recognition memory was evaluated with the novel object recognition task, and the radial water maze test was selected to assess rats' spatial memory. The ability of the CB1R antagonist, SR141716A, to counteract WIN55,212-2-induced behavioral effects was also tested. WIN55,212-2 (0.3, but not 0.03 or 0.1mg/kg) disrupted non-associative learning, different aspects of short- and long-term recognition memory (storage and retrieval) and retention of spatial memory. The 0.3mg/kg dose of WIN55,212-2 also decreased ambulatory, but not vertical (rearing), activity in non-habituated rats. These effects appeared to be CB1R dependent since pretreatment with SR141716A (0.03 mg/kg) prevented the WIN55,212-2-induced behavioral effects. The present findings further support and extend the complex impact of exogenous cannabinoids on learning and memory in relation to their effects on locomotion.

Effects of the active constituents of Crocus Sativus L., crocins, in an animal model of obsessive-compulsive disorder.

Crocins are among the active components of the plant Crocus Sativus L. C. Sativus L. and its constituents were effective in different models of psychiatric disorders including anxiety and depression. Obsessive-compulsive disorder (OCD) is a common psychiatric disorder defined by the presence of obsessive thoughts and repetitive compulsive actions. The non selective serotonin (5-HT) receptor agonist mCPP is known to induce OCD-like behavior (excessive self-grooming) in rodents and exacerbate symptoms in patients with OCD. The present study investigated whether or not crocins were able to counteract excessive self-grooming induced by mCPP (0.6 mg/kg, i.p.) in rats. Crocins (30 and 50mg/kg, i.p.) attenuated mCPP-induced excessive self-grooming. The present results also indicate that these effects of crocins on an animal model of OCD cannot be attributed to changes in locomotor activity. Our findings suggest that the active constituents of C. Sativus L. crocins might play a role in compulsive behavior and support a functional interaction between crocins and the serotonergic system.

Effects of the active constituents of Crocus sativus L., crocins, in an animal model of anxiety.

Crocus sativus L. is a plant cultivated in various parts of the world. Crocins are among the active components of Crocus sativus L. The present study was designed to investigate in the rat whether or not crocins possess anxiolytic properties. For this aim, the light/dark test was selected. Either crocins, at a dose which did not influence animals' motor activity (50mg/kg), or diazepam (1.5 mg/kg), significantly increased the latency to enter the dark compartment and prolonged the time spent in the lit chamber in the rats. Conversely, lower doses of crocins (15-30 mg/kg) did not substantially modify animals' behaviour. The present results indicate that treatment with these active constituents of Crocus sativus L. induce anxiolytic-like effects in the rat.