Master regulatory molecule for brain wiring identified

November 22nd, 2007 - 12:45 pm ICT by admin  

Washington, Nov 22 (ANI): A master regulatory molecule, which is responsible for triggering the remodelling of neuronal connections that is critical for learning, has been identified by a research co-authored by an Indian researcher.

The study, led by Peter Penzes, co-authored by Deepak P. Srivastava and team, which identified the malfunctioning of the connection-remodelling machinery, might also play a role in mental retardation, schizophrenia, and drug addiction.

In the study, the scientists sought to understand the biological machinery controlling the enlargement of mushroom-like structures called dendritic spines on neurons.

Dendrtic spines are the receiving stations for neurotransmitters, signalling chemicals that one neuron launches to trigger a nerve impulse in its neighbour. During learning, these spines strengthen signalling between neurons during the process of laying down memory pathways in the brain.

The researchers have found abnormal dendritic spines in certain types of mental retardation, including autism spectrum disorders, as well as schizophrenia and drug addiction.

The team specifically wanted to discover whether a molecule called kalirin-7 played a role in spine enlargement in mature neurons when they undergo a learning-related strengthening called long-term potentiation (LTP).

The researchers theorized that kalirin-7 might be a key regulator of spine development because it is found in high concentration in the spines of mature neurons.

Also, kalirin-7 was known to play a role in the remodelling of the structural beams and studs of the cell, called the cytoskeleton.

The researchers experiments with cultured neurons revealed that activation of neurons during LTP does indeed trigger kalirin-7 to turn on the machinery for remodelling spines, causing spines to become enlarged.

Scientists concluded that their findings strongly suggest that kalirin-7 may be an important regulator of the experience-dependent modifications of forebrain circuits during postnatal development and may play an important role in learning and memory.

They also pointed out that altered spine structures have been associated with mental retardation, neuropsychiatric disorders, and drug addiction. Specifically, aberrant spine morphology in forebrain occurs in many types of mental retardation, including fragile-X and autism spectrum disorders.

Therefore, our results may suggest potential strategies for treatments of these neurodevelopmental and psychiatric diseases, the researchers stated.

The study is issued in the journal Neuron. (ANI)

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