NOS2 and ischemia: Although, to our knowledge, no drug directly targeting NOS isoforms has been investigated in clinical trials for fear or anxiety-related disorders, one NOS inhibitor (Ronopterin-VAS203) and one Discs large homolog 4 inhibitor/NMDAR antagonist (Nerinetide-NA1 tat-NR2B9c) are currently being tested in Phase 3 clinical trials for traumatic brain injury (TBI) and/or ischemia [284].