interaction between l-type calcium channels and antagonist of cannabinoid system on anxiety in male rat

conclusions ip injection of cb1 receptor antagonist might have an anxiogenic profile in rat, whereas calcium channel blocker attenuated the anxiogenic effect of am251. our results suggest that there is an interaction between functions of l-type ca2+ channels and cannabinoid system in anxiety. background the elevated plus-maze (epm) has been broadly used to investigate anxiolytic and anxiogenic compounds. there is little information about the effect of interaction between calcium channels and cannabinoid system on the phenomenon of anxiety. objectives this study aimed to examine the effects of acute and chronic coadministration of am251, as cannabinoid cb1 receptor antagonist, and verapamil, as l-type ca2+ channels blocker, on epm test in rats. materials and methods the data were obtained from male wistar rat, weighing 220 to 260 g. animals were allocated to five groups: control, verapamil, am251, acute verapamil + am251, and chronic (injection for 8 days) verapamil + am251 groups. the percentage of entries into the open arms of the epm, the time spent in the open arms, and the number of entries into the closed arms during ten minutes was recorded. results intraperitoneally (ip) injection of am251 before epm trial decreased open arms exploration and open arm entry. on the other hand, verapamil increased open arms exploration and open arm entry. combined injection of verapamil and am251 had conflicting effects on the responses of each of these two compounds alone. am251 and verapamil had no effects on the number of closed arm entries.