NOS1 and schizophrenia: The NMDA-nNOS-cGMP pathway is impaired in schizophrenia, and SNP treats schizophrenia by complementing the NMDA-nNOS-cGMP pathway.[38] The D1/D2 mixed receptor agonist apomorphine dose-dependently impairs short-term recognition memory in rats, but SNP reduces apomorphine amnesia by blocking the stimulation of D1/D2 mixed receptors by apomorphine thereby improving cognitive impairment.[39] Schizophrenia is associated with oxidative stress, while apomorphine[40] and ketamine[41] can increase oxidative stress in the mouse brain thereby causing neurocognitive impairment.