HTR2A and stroke disorder: 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.