Selank Peptide's Effects Vary by Delivery Method and Mouse Strain

The synthetic heptapeptide Selank is known for its anxiolytic (anxiety-reducing) and nootropic (cognition-enhancing) properties. Its therapeutic potential is influenced by how it's administered and individual biological differences. However, a direct comparison of its pharmacological effects across different administration routes and genetic backgrounds has been less explored. This study aimed to systematically compare the anxiolytic and behavioral effects of Selank after intranasal versus intraperitoneal administration in two distinct mouse strains, BALB/c and C57BL/6, to identify optimal delivery methods and strain-specific responses.

Intranasal Selank demonstrated a significantly faster onset of anxiolytic effects in BALB/c mice, reducing anxiety-like behaviors by 35% at 30 minutes post-administration compared to a 15% reduction with intraperitoneal delivery (p<0.01). In contrast, C57BL/6 mice showed comparable anxiolytic effects across both routes, but intraperitoneal Selank uniquely led to a 2.1-fold increase in locomotor activity (p<0.05) not observed with intranasal administration. The duration of effect also differed; intranasal effects in BALB/c mice peaked at 60 minutes and began to wane by 90 minutes, while intraperitoneal effects in C57BL/6 mice were sustained for up to 120 minutes, showing a 25% reduction in anxiety. This suggests route-dependent pharmacokinetics. The most significant finding was that intranasal administration of Selank in BALB/c mice resulted in a 43% greater anxiolytic effect at the 60-minute mark compared to intraperitoneal injection, indicating superior bioavailability and efficacy for this specific strain and route.