Background and Aim: Cannabinoids are compound divided into two groups depend on where they are produced: endo- and exo- cannabinoids. Their activity involves endocannabinoid system which consist of Cannabinoid G-protein coupled (〖〖CB〗_1 ,CB〗_2) and non-cannabinoid receptors, endogenous ligands and enzymes which produce and metabolize cannabinoids. Anti-Nausea and anti- spastic effects are among results of activity of this system. Some of exogenous cannabinoids are present in marijuana. In this research we are to investigate effects of injection of acute hexane extract on motor coordination. Methods: First, 50g marijuana was heated in 180°C for 10 minutes and hexane extract was produced from it. Then 18 male wistar rats weighing 250-300g grouped into 3 (each consist of 6 rats) for injection: control group with no injection, sham group with i.p. injection of the solution used as vehicle (Tween 80, ethanol and saline with 1/1/8 proportions) and the last group with i.p. injection of the extract in 50mg/kg dosage. Each group was evaluated with rotarod apparatus in order to investigating motor coordination. Results: marijuana extract respect to control and sham groups could significantly (P<0.01) decreases the time of staying of rats on rotarod cylinder therefore decreases their motor coordination. Conclusion: cannabinoid receptors especially 〖CB〗_1 are presents in different parts of central nervous system as central cannabinoid system. Axons and axon terminals of basal ganglia, brain cortex, Granular cells of molecular layer with cerebral basket and purkinje cells as effective regions in control of coordination have a high density of 〖CB〗_1 receptors. Activating this receptor in pre- synaptic neuron inhibits adenylyl cyclase and production of cAMP thus surpasses release of synaptic mediators such as glutamate. Beside the endocannabinoid system also interacts with opioid and adenosine system which have roles in movement and coordination. Thus we can conclude that heat may decarboxylate cannabinoids which are presented in marijuana and the decarboxylated form shows maybe more affinity to 〖CB〗_1 receptors and this connection may decrease motor coordination.

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