Background and Aim: Beta-adrenergic receptors in the basolateral nucleus of the amygdala (BLA) have been associated with stress, learning, and memory. In this study, we tested the effects of intra-BLA microinfusions of the β₂-adrenergic receptor agonist, salbutamol, on spatial, passive avoidance memory and long-term potentiation (LTP) in the CA1 region of the hippocampus in response to stress.
Materials and Methods: Forty male rats were randomly divided into five groups (n=8/per group): control, sham, stress, salbutamol+control, and salbutamol+stress. Bilateral cannulation was performed in the BLA, by using stereotaxic apparatus. Then, the rats were transferred to the communication box and foot-shock stress induction continued for four consecutive days. Five minutes before stress, salbutamol (4 µl/side) was injected bilaterally into the BLA. Barnes maze and shuttle box were examined for spatial and passive avoidance memory, respectively. The field potential recording was also used to investigate LTP in the CA1 neurons of the hippocampus.
Results: The results of the passive avoidance test showed that bilateral injection of salbutamol in the BLA five minutes before stress increased step-through latency time significantly compared to the stress group. Barnes maze results showed that intra-BLA microinfusions of salbutamol before stress, reduced the latency time, the number of errors, and the distance traveling to achieve the target hole compared to the stress group. Field potential recording revealed that salbutamol injection before stress decreased the population spike amplitude significantly and caused fEPSP slope 60 minutes after high-frequency stimulation compared to the stress groups.
Conclusion: It seems that the salbutamol in the BLA can improve memory deficits induced by stress.