Glutamatergic and cholinergic makes it sound like it would be excitotoxic for the parasympathetic nervous system.
Yep, thanks for saying this. One of the reasons I have reservations about this chemical and other highly specific 5-Ht1A antagonists. Many other 5-HT1A receptor antagonists were dropped from considerations due to issued with side effects. In fact, one of them was specifically tested for reversing the effects of SSRI but the clinical trial failed.
Robalzotan - Wikipedia
The ones that look more promising are these:
NAN-190 - Wikipedia
Isamoltane - Wikipedia
Dotarizine - Wikipedia