U.S scientists identify chemicals that grow brain cells

Researchers at the Emory University School of Medicine in Atlanta have identified chemicals that help to grow neurons in the brains of mice, potentially leading to new treatments for mental illness and cognitive disabilities.

Following an in vivo screen, eight of 1000 small molecules tested were shown to enhance neuron formation in key parts of rodent’s brains linked to memory and learning. Of these eight molecules, an aminopropyl carbozole designated P7C3, was shown to exert its own proneurogenic activity by protecting newborn neurons from apopstosis.

Those mice missing the gene encoding neuronal PAS domain protein 3 (NPAS3) were found to be devoid of neurogenesis in the hippocampus and displayed brain malformation and dysfunction. When administered P7C3, these deficits were corrected through the normalisation of apoptosis of newborn neurons in the hippocampus. Ongoing administration of P7C3 to NPAS3 also resulted in improved neurogenesis in the dentate gyrus, reduced neuron death while maintaining cognitive abilities.

NPAS3 is a central nervous system-specific transcription factor and is widely associated with mental illness and cognitive disabilities. It is hoped that drugs able to stimulate its activity could result in normalised brain activity for sufferers of myriad conditions from Alzheimer's to depression and learnign disabilities.

The researchers said that there was now evidence of at least eight neurogenic and neuroprotective compounds, with the most promising P7C3 possessing several benefits including being orally available, having a long half-life, ability to cross the brain blood barrier as well as being safely tolerated by mice.

The Emory University study builds on the breakthrough research of revered American neuroscientist Fernando Nottebohm (Paton and Nottebohm 1984), who studied the learning of songs by birds to show that the adult brain supports the birth and incorporation of new neurons.

It is now firmly established that all mammals, including humans, possess reservoirs of neuronal stem cells. Further, environmental factors such as exercise are known to stimulate the development of new neurons, while genetic and chemical variables also play a part. For instance, studies have shown that rodents and humans administered anti-depressants experience increased neuron production.