Cell Press

Nicotine withdrawal traced to very specific group of brain cells.

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Nicotine withdrawal might take over your body, but it doesn’t take over your brain. The symptoms of nicotine withdrawal are driven by a very specific group of neurons within a very specific brain region, according to a report in Current Biology, a Cell Press publication, on November 14. Although caution is warranted, the researchers say, the findings in mice suggest that therapies directed at this group of neurons might one day help people quit smoking.

“We were surprised to find that one population of neurons within a single brain region could actually control physical nicotine withdrawal behaviors,” says Andrew Tapper of the Brudnick Neuropsychiatric Research Institute at the University of Massachusetts Medical School.

Tapper and his colleagues first obtained mice addicted to nicotine by delivering the drug to mice in their water for a period of 6 weeks. Then they took the nicotine away. The mice started scratching and shaking in the way a dog does when it is wet. Close examination of the animals’ brains revealed abnormally increased activity in neurons within a single region known as the interpeduncular nucleus.

When the researchers artificially activated those neurons with light, animals showed behaviors that looked like nicotine withdrawal, whether they had been exposed to the drug or not. The reverse was also true: treatments that lowered activity in those neurons alleviated nicotine withdrawal symptoms.

That the interpeduncular nucleus might play such a role in withdrawal from nicotine makes sense because the region receives connections from other areas of the brain involved in nicotine use and response, as well as feelings of anxiety. The interpeduncular nucleus is also densely packed with nicotinic acetylcholine receptors that are the molecular targets of nicotine.

It is much less clear whether the findings related to nicotine will be relevant to other forms of addiction, but there are some hints that they may.

“Smoking is highly prevalent in people with other substance-use disorders, suggesting a potential interaction between nicotine and other drugs of abuse,” Tapper says. “In addition, naturally occurring mutations in genes encoding the nicotinic receptor subunits that are found in the interpeduncular nucleus have been associated with drug and alcohol dependence.”

Source: Cell Press

Lung Cancer Signatures in Blood Samples May Aid in Early Detection.

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Lung cancer is one of the most common and deadly types of cancer. Mouse models of lung cancer recapitulate many features of the human disease and have provided new insight about cancer development, progression and treatment. Now, a new study published by Cell Press in the September 13th issue of the journal Cancer Cell identifies protein signatures in mouse blood samples that reflect lung cancer biology in humans.

The research may lead to better monitoring of tumor progression as well as blood based early detection strategies for human lung cancer that could have a substantial impact on disease prognosis.

“In our study, we applied a comparative strategy of genetically engineered mouse models of cancer and integrated data at the genome and protein levels to uncover lung cancer signatures in blood samples that reflect different types of lung cancer, or that reflect signaling pathways driving tumor development,” says senior study author, Dr. Samir M. Hanash, from the Fred Hutchinson Cancer Research Center in Seattle. In order to identify blood protein signatures common to lung cancer, Dr. Hanash and colleagues looked at the proteins in the blood plasma of several different mouse lung tumor models and compared the proteins with those in models of other types of tumors.

The researchers identified individual protein signatures for molecularly distinct types of lung cancer and discovered that the networks of proteins provided insight into the genes that drive tumor development. Further, they identified proteins which were restricted to the blood samples from the lung cancer models and were not previously linked with lung cancer.

The authors went on to demonstrate the relevance of the protein signatures identified in the mouse models to human lung cancer. “We obtained evidence for concordant findings in human lung cancer cell lines and in plasmas collected from subjects with lung cancer at the time of diagnosis and in blood samples collected from asymptomatic subjects prior to diagnosis. These findings point to the power of integrating multiple types of studies and data to uncover lung cancer markers and may lead to early detection strategies for humans as well as strategies for monitoring tumor status in patients with the disease,” says Dr. Hanash.

Source: http://www.sciencedaily.com

 

Human Brains Outpace Chimp Brains in Womb.

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Humans‘ superior brain size in comparison to their chimpanzee cousins traces all the way back to the womb. That’s according to a study reported in the September 25 issue of Current Biology, a Cell Press publication, that is the first to track and compare brain growth in chimpanzee and human fetuses.

“Nobody knew how early these differences between human and chimp brains emerged,” said Satoshi Hirata of Kyoto University.

Hirata and colleagues Tomoko Sakai and Hideko Takeshita now find that human and chimp brains begin to show remarkable differences very early in life. In both primate species, the brain grows increasingly fast in the womb initially. After 22 weeks of gestation, brain growth in chimpanzees starts to level off, while that of humans continues to accelerate for another two months or more. (Human gestation time is only slightly longer than that of chimpanzees, 38 weeks versus 33 or 34 weeks.)

The findings are based on 3D ultrasound imaging of two pregnant chimpanzees from approximately 14 to 34 weeks of gestation and comparison of those fetal images to those of human fetuses. While early brain differences were suspected, no one had previously measured the volume of chimpanzee brains as they develop in the womb until now.

The findings are part of a larger effort by the research team to explore differences in primate brains. In another Current Biology report published last year, they compared brain development in chimps versus humans via magnetic resonance imaging (MRI) scans of three growing chimpanzees from the age of six months to six years.

“Elucidating these differences in the developmental patterns of brain structure between humans and great apes will provide important clues to understand the remarkable enlargement of the modern human brain and humans’ sophisticated behavior,” Sakai said.

The researchers say they now hope to explore fetal development in particular parts of the brain, including the forebrain, which is critical for decision making, self-awareness, and creativity.

Source: http://www.sciencedaily.com