NOS1 and Anxiety: To directly investigate the role of the nNOS–NO pathway in mediating anxiety-like behaviors induced by the activation of nNOS-expressing neurons, we took nNOS-Cre mice that had been microinjected with AAV-hSyn-DIO-hM3Dq-eGFP in the vmPFC, and we treated them with l-VNIO or NS 30 min after CNO delivery (day 21).