Semax Exhibits Dual Effects on Avoidance Learning and Memory Recovery in Rats

Semax, a synthetic peptide analog of ACTH (adrenocorticotropic hormone), is widely recognized for its nootropic properties, which include enhancing cognitive functions like memory and learning. Despite its established benefits, the specific influence of Semax on various forms of active avoidance conditioning and its role in restoring these responses after functional disturbances have not been fully elucidated. This study aimed to investigate Semax's context-dependent effects on both the acquisition and subsequent recovery of avoidance behaviors in rats across different experimental paradigms.

The study revealed that Semax's effects on avoidance learning were highly dependent on the experimental context. In the one-way active avoidance task, Semax administration significantly accelerated the acquisition of the avoidance response, indicating enhanced learning efficiency. Conversely, in the more demanding shuttle-box model, Semax increased the electroshock threshold value required to provoke movement, suggesting a modulation of pain perception, which in turn delayed the acquisition of the two-way active avoidance response. Most importantly, Semax robustly stimulated the restoration of avoidance responses in the shuttle-box after functional disturbances induced by acute modifications of the cause-effect and spatial relationships in the experimental environment, demonstrating enhanced cognitive flexibility and recovery. These findings highlight Semax's complex nootropic influence, modulating both pain sensitivity and facilitating memory recovery in a task-specific manner.