Paired-pulse Inhibition and Disinhibition of the Dentate Gyrus Following Orexin Receptors Inactivation in the Basolateral Amygdala

Introduction: The Basolateral Amygdala (BLA) subsciantially affects neuronal transmission and synaptic plasticity processes through the dentate gyms. Orexin neuropeptides play different roles in the sleep/wakefulness cycle, feeding, learning, and memory. The present study aimed to investigate the function of the orexin receptors of the BLA in the hippocampal local interneuron circuits. Methods: For this, the region's paired-pulse responses from the Dentate Gyms (DG) were recorded. Within the procedure, SB-334867-A (12 mu g/0.5 mu L) and TCS-OX2-29 (10 mu g/0.5 mu L (orexin 1 & 2 receptors antagonists, respectively), were administered into both sides of the BLA areas of the rat brain. Dimethyl Sulfoxide (DMSO) was used as the solvent in the control animals with a volume of 0.5 mu L. Results: Our data indicated that the Paired-pulse (PP) responses were not affected by the inactivation of the orexin receptors of the BLA. Conclusion: Due to not observing any significant changes in the short form of synaptic plasticity, after inactivation of the orexin system of the BLA, we hypothesize that the orexinergic fibers to the basolateral part of the amygdala influence the long-term synaptic efficacy; however, the primary processing of information in short-term plasticity model is not affected by the same system. The elementary processing of the data by the amygdala might happen through the action of other neurotransmitter system.