Rodents

People who exercise are less likely to have a heart attack, studies show. Moreover, physically active people who do have a heart attack may not sustain as much heart damage compared to sedentary heart-attack patients. Now researchers have a better understanding of why exercise is so protective. In a recent study, scientists found that the heart is able to produce and store a natural substance called nitric oxide that helps strengthen the heart muscle. Nitric oxide is produced during exercise.

We've all had them, and scientists now know what brain glitches look like. Certain parts of the brain can briefly shut down while the rest of the brain is functioning, a new study shows. These micro naps may help explain why people sometimes do mindless things, like leaving the key in the front door. Researchers at the University of Wisconsin conducted an experiment with rats to explore the phenomenon of micro sleep. The longstanding theory has been that any momentary loss of consciousness affects the entire brain.

One of the mysteries of autism is why an infant who seems to be developing normally suddenly regresses after his or her first birthday. This phenomenon, which affects about 25% of children diagnosed with autism, gave rise to the now-discredited hypothesis that immunizations given around the first birthday can cause the disease. A study published Thursday in mice provides a potential explanation of what happens in the brains of these children. Researchers at Children's Hospital Boston conducted experiments with mice with a mutation in the Mecp2 gene.

Drinking at a young age is simply bad for the brain, according to a growing number of studies. The latest study looks at the relationship between alcohol and the brain in mice. And the results are not pretty. Researchers gave mice alcohol daily for 10 days and later examined their brains with MRI. The mice who were drinkers in youth had smaller forebrain volume and size as adults. The study also found reduced activity in some genes that govern brain chemicals called neurotransmitters 24 hours after an alcohol binge in adolescent mice.

An experimental drug appears to decrease tumor size in mice with cancer without causing serious side effects, researchers from the University of Michigan reported this week. The compound, called AT-406, affects apoptosis, which governs the normal cell turnover process. When apoptosis is disrupted, cells don't die on the correct timetable but, instead, keep reproducing uncontrollably. That gives rise to cancer. The drug removes the barriers to apoptosis in tumor cells, said the lead author of the study, Shaomeng Wang, whose lab has been working on AT-406 for five years.

The synapses are areas in the brain that permit messages to travel from cell to cell through chemicals called neurotransmitters. A study published this week suggests that autism may caused by faulty synapses. The new study was launched with the knowledge that some genes seem to contribute to autism, including a gene called shank3 that is found in the synapses. Researchers led by Guoping Feng, a professor of brain and cognitive sciences at the McGovern Institute for Brain Research at MIT, decided to test the concept that autism may be caused by dysfunctional synapses.

Any devoted reader of the Rodent of the Week knows by now how much science depends on our furry friends. Without them, we would know next to nothing. That's why this week's news of a better way to study rats' brains deserves notice. Researchers reported they have developed a wearable, portable PET scanner that will measure the rodent brain function while the animals are awake and moving. The device was developed by scientists from the U.S. Department of Energy's Brookhaven National Laboratory, Stony Brook University.

A drug that could halt the progression of Parkinson's disease is successful in mice and is now being evaluated in human patients, researchers reported this week.   The drug is phenylbutyrate, which is already on the market as an orphan drug for treatment of infants with a rare genetic disorder called urea cycle disorder . Research at the University of Colorado School of Medicine shows that the medication turns on a gene that can protect dopamine neurons. It's the destruction of nerve cells that produce dopamine that leads to the stymptoms of Parkinson's disease, such as loss of movement.

One of the high-profile areas of research for stem cells is in treatment of spinal cord injuries -- and there was progress to report this week. Researchers were able to transplant a type of human cell into rats with spinal cord injuries to help the animals regain some motor function. Previous studies have shown that certain types of rat cells are necessary to repair spinal cord injuries. But the new study "brings it up to a human level," said Chris Proschel, the lead author of the paper and an assistant professor of genetics at the University of Rochester Medical Center.

Fructose is a simple sugar found in honey and in smaller amounts in some fruits and vegetables. The impact of fructose in the human diet has been the subject of some controversy. Higher fructose consumption has been linked to weight gain in humans. A new study in rats suggests that high doses of fructose in pregnancy may not be a good thing, either, especially for female offspring. Researchers in New Zealand gave pregnant rats either water or a fructose solution designed to provide about 20% of the rats' daily calories.