Effects of Intra-hippocampal Administration of Alpha-pinene on Learning and Memory Performances in Adult Male Rats

Alpha-pinene (α-pinene) is a bicyclic monoterpene present in essential oils of some aromatic plants. α-pinene is involved in modulation of some neurophysiological processes in animals. This study assessed the effect of intra-CA1 administration of α-pinene on spatial and passive avoidance learning and memory, and induction of long-term potentiation (LTP) in hippocampal CA1 region.

Male Wistar rats were cannulated in the CA1 area of hippocampus. Then, α-pinene (0.1, 0.2, and 0.4 µg) was injected in four consecutive days. Passive avoidance and spatial learning and memory were assessed by shuttle box and Morris water maze (MWM) tasks, respectively. Also, in vivo recording of field excitatory postsynaptic potentials (fEPSPs) in hippocampal CA1 region was done.

In MWM test, α-pinene decreased latency time and travelled distance to find the hidden platform (P<0.05). In the shuttle box, α-pinene increased the step thought latency and decreased the time spent in dark chamber of maze compared to the control group (P<0.001). There were no significant differences in induction of LTP in the CA1 area of the hippocampus between the controls and α-pinene group (P<0.05).

Intra-CA1 administration of α-pinene affected learning and memory of rats. However, α-pinene did not induce significant alteration in induction of LTP in hippocampal CA1 region.