Table 1.

Literature review results

Dosage	Population	Results	Study
10–100μM sildenafil	HT-22 hippocampal neuronal cells exposed to Aβ 25 - 35	Sildenafil rescued mitochondrial Ca2 + overload and dysfunction due to Aβ 25 - 35 by opening ATP-sensitive K + channels	[140]
20μM sildenafil	HT-22 hippocampal neuronal cells exposed to advanced glycation end products	Sildenafil decreased mitochondrial permeability transition pore opening and apoptosis via HO1 upregulation	[141]
Variable, 3 mg/kg	Scopolamine-induced cholinergic dysfunction mice	Sildenafil rescued memory	[143]
Variable, primarily 3 mg/kg/day intraperitoneal sildenafil	APP/PS1 mice	Sildenafil rescued long-term potentiation, CREB phosphorylation, memory, and decreased Aβ levels	[144]
6 mg/kg, intraperitoneal daily for 3 months	APP/PS1 mice	Sildenafil improved memory, amyloid plaque load, inflammation, and neurogenesis	[145]
2 mg/kg sildenafil twice daily for 4 months	APP/PS1 mice	Sildenafil rescued memory and amyloid pathology, downregulated PDE5, and increased NOS, NO, and cGMP levels	[146]
Sildenafil was dissolved in 0.9% saline at a concentration of 1.0 mg/ml. 10.0 mg/kg of this solution was administered intraperitoneally with an injection volume of 0.1 ml/10 g.	APP/PS1 mice	Sildenafil improved memory, decreased levels of Aβ, IL-1β, IL-6 and TNF-α, and increased p-CREB	[147]
15 mg/kg sildenafil daily for 10 weeks in water	J20 mice	Sildenafil improved memory, tau hyperphosphorylation, and Akt and GSK3β phosphorylation, but not prefrontal cortex Aβ 42 levels	[61]
15 mg/kg daily sildenafil, intraperitoneal	Tg2576 AD mice	Sildenafil improved memory, tau but not frontal cortex amyloid pathology, inhibited GSK3β, decreased CDK5 p25/35 ratio, upregulated BDNF and Arc	[148]
Variable	Aged mice	Sildenafil improved spatial memory retention but not acquisition	[64]
3 mg/kg intraperitoneal sildenafil daily for 3 weeks	Aged mice	Sildenafil decreased double-stranded DNA breaks and pro-apoptotic caspase-3 and Bax and upregulated antiapoptotic Bcl2 and BDNF	[149]
7.5 mg/kg sildenafil intraperitoneally once daily for 4 weeks	SAMP8 mice	Sildenafil improved amyloid and tau pathology, memory, and gliosis	[145, 150]
7.5 mg/kg sildenafil intraperitoneally once daily for 4 weeks	SAMP8 mice	Sildenafil decreased JNK phosphor-activation in the hippocampus, tau phosphorylation, and memory deficits	[151]
50 mg sildenafil, single dosage	10 AD patients	Sildenafil decreased spontaneous neural activity in right hippocampus	[152]
50 mg sildenafil, single dosage	14 AD patients	Sildenafil increased cerebral metabolic rate of oxygen and cerebral blood flow in 12 patients, decreased cerebral vascular reactivity in 8 patients	[127]