Proteins necessary for brain development found to be critical for long-term memory

Sep 05, 2006

A type of protein crucial for the growth of brain cells during development appears to be equally important for the formation of long-term memories, according to researchers at UC Irvine. The findings could lead to a better understanding of, and treatments for, cognitive decline associated with normal aging and diseases such as Alzheimer's.

The findings appear in the early online edition of the Proceedings of the National Academy of Sciences.

"This study presents strong evidence that a molecular process fundamental during development is retained in the adult and recycled in the service of memory formation," said Thomas J. Carew, Donald Bren Professor and chair of UCI's Department of Neurobiology and Behavior. "It is a striking example of how molecular rules employed in building a brain are often reused for different purposes throughout a lifetime."

The researchers have shown that proteins known as growth factors are as essential for the induction of long-term memory as they are for the development of the central nervous system. These growth factors, such as brain derived neurotrophic factor (BDNF), bind onto the brain cell through a specific type of receptor known as TrkB, much the same way a key fits into a lock. As an experimental strategy to determine the importance of BDNF-like growth factors in forming memories, the researchers used a "molecular trick" to keep the proteins from binding with the appropriate TrkB receptors.

For the experiment, the scientists used wild-caught Aplysia, a marine snail frequently studied in learning and memory because of its large brain cells. The Aplysia received a series of five tail shocks, spaced 15 minutes apart. The shocks cause the animals to exhibit heightened withdrawal reflexes days and weeks after the shocks are over.

When the animals are shocked, a brain chemical known as serotonin is released that promotes the formation of a long-term memory associated with the shocks. However, when Carew and his colleagues blocked the interaction between the BDNF-like growth factors and the TrkB receptors, they found that serotonin alone was not enough to retain the long-term memory of the shock. While short-term memory was retained, 24 hours later the snails -- which normally would remember the events of the previous day -- exhibited no memory of the shocks. Carew and colleagues went on to show that, when the actions of the growth factors were prevented, long-term enhancement of the connections between the brain cells in the reflex circuit normally induced by the shock treatment was also blocked.

"We would never have expected that the secretion of these growth factors in response to serotonin would be critical for long-term memory formation in this system," Carew said. "But it is apparent that without them, this process cannot happen."

According to Carew, these findings could open possible avenues for treatments relating to memory loss. "This gives us some strong clues as to what we should be looking into for therapeutic interventions," he said. "If we know that growth factors are important for long-term memory, then we can look at possible remedial roles they might play in diseases such as Alzheimer's and dementia."

Source: University of California, Irvine

Explore further: Test shows Spain nursing assistant clear of Ebola

add to favorites email to friend print save as pdf

Related Stories

Google profit dips to $2.8 bn

4 hours ago

Google said Thursday its profit in the past quarter dipped slightly from a year earlier, even as revenues for the technology giant showed a sharp increase.

Shrinking resource margins in Sahel region of Africa

5 hours ago

The need for food, animal feed and fuel in the Sahel belt is growing year on year, but supply is not increasing at the same rate. New figures from 22 countries indicate falling availability of resources per ...

Recommended for you

Mum's health plays greater part in premmie babies

16 minutes ago

An international study on premature babies has found medical conditions such as chronic hypertension and pre-eclampsia play a greater role in the untimely birth and not the mother's sociodemographic status, ...

Magnesium cuts diabetes risk

32 minutes ago

Getting enough magnesium in the diet may reduce the risk of diabetes, especially for those who already show signs of heading that way.

iPads detect early signs of glaucoma in Nepal eye screening

1 hour ago

Using a tablet screening app could prove to be an effective method to aid in the effort to reduce the incidence of avoidable blindness in populations at high-risk for glaucoma with limited access to health care, according ...

Invading worms cause the body to shut down defenses

1 hour ago

When parasitic worms invade muscle tissue, white blood cells called eosinophils rush to the scene. A study published in the Journal of Immunology this month reveals that these cells actually start a chai ...

User comments : 0