Giving the brain‑boosting peptide Semax to newborn mice changes how they behave as adults, affecting things like seizure risk, anxiety, curiosity and pain feeling. Some of these changes are the same as what you’d see if you gave the drug to grown‑up animals, while others are the opposite. The effects also depend on the animal’s genetics, suggesting early brain development is very sensitive to such drugs.

Experimental data were reviewed which demonstrated that the neonatal injection effects of certain biologically active drugs (ACTH(4-10) fragment and its analogue Semax, piracetam, caffeine, levetiracetam, busperone, etc.) could be detected in adult animals as changes in physiological and behavioral reactions and in several morphological traits as well. Audiogenic seizures proneness, anxiety-fear and exploration behavior as well as pain sensitivity were analyzed. The remote effects discovered were either similar in direction to those applied to an adult organism, or opposite to it. Pharmacological treatments of such type presumably interfere the CNS development during early postnatal ontogeny and change the normal pattern ofbrain development. These modulatory influences could be due to changes in neurotransmitter system development and are presumably capable to induce CNS morphological deviations (numbers of neurons, adult neurogenesis).