Table 2.

Brain and serum concentrations of sildenafil following different dosing modes

Treatment		Brain concentration (μg/g)	Serum concentration (μg/ml)	n
acute	sildenafil 60 mg/kg	9.72 ± 1.07	10.98 ± 0.94	12
subchronic	sildenafil 60 mg/kg	not detectable	0.04 ± 0.01	12

Data are presented as means ± SEM. In acute treatment, sildenafil was administered at a dose of 60 mg/kg, 30 min before decapitation. In chronic treatment, sildenafil was injected for 14 days at a dose of 60 mg/kg and decapitation was performed 24 h after the last injection