Phosphodiesterase 5 inhibitors alter brain frequency bands and lower seizures threshold in rats.

BACKGROUND: Phosphodiesterase 5 inhibitors (PDE5i) are the first line treatment for erectile dysfunction; however, several articles and case reports have shown central nervous system effects, that can cause seizures. This study aims to describe the changes caused by the use of sildenafil and tadalafil through the analysis of abnormalities expressed in the electrocorticogram (ECoG) of rats and evaluate the seizure threshold response and treatment of seizures with anticonvulsants. MATERIALS AND METHODS: The study used 108 rats (Wistar). Before surgery for electrode placement in dura mater, the animals were randomly separated into 3 experiments for electrocorticogram analysis. Experiment 1: ECoG response to the use of PD5i (Sildenafil 20mg/kg and Tadalafil 2.6mg/kg p.o.). Experiment 2: ECoG response to the use of PD5i in association with Pentylenetetrazole (PTZ - 30 mg/kg i.p.), a convulsive model. Experiment 3: ECoG response to anticonvulsant treatment (phenytoin, phenobarbital and diazepam) of seizures induced by association IPDE5 + PTZ. All recordings were made thirty minutes after administration of the medications and analyzed for ten minutes, only once. We considered statistical significance level of *p<0.05, **p<0.01 and ***p < 0.001. RESULTS: After the administration of sildenafil and tadalafil, the ECoG recording showed changes in the energy distribution in the frequency bands, mainly Alpha and Beta. After the use of sildenafil and tadalafil associated with PTZ, greater potency was observed in the recordings during seizures. Phenytoin did not adequately control the models seizures, but phenobarbital and diazepam had performed better. CONCLUSIONS: PDE5i altered the ECoG recordings in the rats motor cortex , demonstrating cerebral asynchrony and potentiating the action of PTZ. These findings demonstrate that PDE5i can lower the seizure threshold