Activation of L-type calcium channels and attenuation of oxidative stress are involved in the improving effect of methyl jasmonate on learning and memory and its anxiolytic property in rats.

Abstract

The present study was designed to evaluate the effect of plant bioactive compound methyl jasmonate on learning and memory, anxiety-like behaviors, and brain oxidative stress in rats. It has been indicated that methyl jasmonate stimulates calcium-binding protein expression and increases intracellular calcium (Ca2+). Therefore, we investigated the potential role of L-type calcium channel on methyl jasmonate effects. The animals were intracerebroventriculary (i.c.v.) injected with different doses of methyl jasmonate (0.5, 2.5, and 5 µg/rat). L-type calcium channel blocker (nifedipine 5 µg/rat, i.c.v.) was injected 30 min before methyl jasmonate (5 µg/rat). Shuttle box apparatus was used to evaluate passive avoidance memory. Anxiety-like behaviors were assessed by open field and elevated plus maze tests. Lastly, oxidative stress-related indices were assessed in hippocampus and prefrontal cortex. The data showed that methyl jasmonate dose-dependently could improve passive avoidance learning and memory and reduce anxiogenic behaviors. The methyl jasmonate effects were significantly prevented by nifedipine. Furthermore, central microinjection of methyl jasmonate significantly decreased hydrogen peroxide concentration, and increased reactive oxygen species scavenger activity (catalase and peroxide enzymes) in rats' hippocampus as well as prefrontal cortex. Indeed, the results indicated that the beneficial effects of methyl jasmonate on learning and memory and anxiety might be partly associated with L-type calcium channel and partly on the inhibition of oxidant indices.