Because there is this study that says it lowers kynurieic acid which is linked to serotonin Cerebrolysin lowers kynurenic acid formation — An in vitro study
And seems to be a gaba b agonist Brain-derived peptides inhibit synaptic transmission via presynaptic GABAB receptors in CA1 area of rat hippocampal slices - PubMed
And seems to be a gaba b agonist Brain-derived peptides inhibit synaptic transmission via presynaptic GABAB receptors in CA1 area of rat hippocampal slices - PubMed