In Vivo: Yonkenafil (Tunodafil) hydrochloride (4-32 mg/kg, i.v. daily for 7 days) improves behavioral outcomes after stroke and reduces cerebral infarct volume, inhibits neuronal apoptosis, and significantly enhances synaptic function in ischemic brain by modulating the expression of BDNF/TrkB and NGF/TrkA.