Effect of low frequency stimulation of olfactory bulb and olfactory epithelium on epileptiform activity and synaptic plasticity following pentylenetetrazol administration in rats
摘要
The effect of olfactory bulb (OB) and olfactory epithelium (OE) electrical stimulation on epileptiform activity and seizure-induced impairment on synaptic plasticity and memory was investigated in anesthetized and freely-moving animals.
MethodsMale Wistar rats were anesthetized with urethane (1.5 g/kg). Stimulating electrodes were bilaterally placed in either the OB or the OE. Another electrode was placed in the CA1 area for recording epileptiform discharges (EDs) following a pentylenetetrazol (PTZ, i.v.) injection and evoked field potentials following Schaffer collateral stimulation. Subjects were divided into PTZ and control groups. Each group received a 1 Hz stimulation either in the OB (OBS) or the OE (OES). ED threshold and duration, and the ability to generate long-term potentiation (LTP) were assessed. Finally, the effect of OBS on acute PTZ-induced seizures and working memory was investigated in freely-moving animals. OBS significantly increased the ED threshold when applied at 250 µA and decreased ED duration when applied at 125 and 250 µA.
ResultsApplying OES had a small effect on the ED threshold but significantly decreased ED duration when applied at 125 and 250 µA. Both OBS and OES mitigated the PTZ-induced increase in basal synaptic transmission. Meanwhile, OBS and OES significantly restored the LTP generation following PTZ injection in anesthetized rats. In addition, applying OBS in freely-moving animals reduced the seizure severity and restored working memory impairment.
ConclusionsOB and OE may be considered effective stimulation targets for the attenuation of epileptiform activity and seizure severity. In addition, both OBS and OES decreased the seizure-induced impairment in LTP generation.
Graphical Abstract