Serotonin (5HT) and GABA, acting through specific receptor subtypes 5HT2 and GABAA, B, control cell proliferation as comitogens.4, 5 Integration of neurotransmitters into biodegradable polymers results in a biomaterial that successfully promotes nerve growth, which is necessary for victims of CNS injury, stroke or certain neurodegenerative diseases to recover sensory, motor, cognitive or autonomic functions. The gene discussed is HTR2A; the disease is neurodegenerative disease.