2-Amino-6-trifluoromethoxy benzothiazole (PK 26124), a proposed antagonist of excitatory amino acid neurotransmission, does not produce phencyclidine-like behavioral effects in pigeons, rats and rhesus monkeys.

PK 26124, a proposed excitatory amino acid antagonist, was compared to mephenesin and phencyclidine (PCP). In pigeons, PK 26124 and mephenesin produced loss of righting that was to some extent associated with eye closure and muscle relaxation, whereas PCP produced catalepsy, i.e., loss of righting without eye closure and without muscle relaxation. PK 26124, but not mephenesin, produced PCP-like discriminative stimulus effects in some but not all pigeons. In rats, PK 26124 and mephenesin produced loss of righting but did not induce locomotion, sniffing, swaying and falling, unlike PCP. In rhesus monkeys, PK 26124 did not induce ketamine-like discriminative stimulus effects. While PK 26124 may share some biochemical properties with excitatory amino acid antagonists these do not lead to behavioral effects similar to PCP.