INTRODUCTION: Vagal nerve stimulation (VNS) is currently approved for treatment of both pharmacologically resistant seizures and severe refractory depression. In addition, VNS is used for treatment of Alzheimer disease, schizophrenia and central inflammation. Interestingly, VNS has also been demonstrated to enhance HPC-induced long-term potentiation (LTP) and improve memory in rats and humans. The above mentioned findings suggest the direct involvement of hippocampal formation (HPC) theta rhythm. AIM(S): We have just recently documented for the first time the presence of HPC type II theta in response to the application of VNS. VNS-induced theta rhythm appeared in different experimental protocols and, depending on the current intensity, could occur directly during VNS (brief effect) or after vagal stimulation (delayed effect). The aim of the present study was to demonstrate that the effect of left VNS on HPC theta rhythm is mediated by medial septum. METHOD(S): Anesthetized rats were implanted with vagal cuff electrodes and unilaterally with HPC recording tungsten electrode. The VNS (8 mA, 500 us, 10 s) were applied three times: before HPC injection of procaine (control), 10 min after and 60 min after. The EEG signals were analyzed off‑line using the Spike‑2 software computing system (Cambridge Electronic Design, Cambridge, UK). RESULTS: We demonstrated that medial-septal procaine injection reversibly abolished HPC type II theta rhythm induced by VNS in anesthetized rats. CONCLUSIONS: We believe that the present findings concerning type II theta rhythm open a new perspective into the study of vagal nerve involvement in central processes of sensory-motor integration, cognition and memory.
JavaScript jest wyłączony w Twojej przeglądarce internetowej. Włącz go, a następnie odśwież stronę, aby móc w pełni z niej korzystać.