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Vol. LVII, No. 15
July 15, 2005
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Students See Connections

Summer brings students to work in the labs, and there are plenty of intriguing talks given for their benefit over the summer weeks. A pair of recent lectures complemented each other nicely and gave insight into how research can progress on a problem from multiple angles.

The University of Cambridge's Dr. Stephen O'Rahilly wound up the 2004-2005 Wednesday Afternoon Lecture Series on June 29 with a talk about human obesity and insulin resistance. His group studies families with extreme phenotypes and focuses on interesting candidate genes. Leptin is probably the best known of these findings, but O'Rahilly described several other intriguing genes his lab is studying.

It was interesting to see how Dr. Yavin Shaham's talk at the summer lecture series for students complemented the final WALS lecture. Shaham, from NIDA's Behavioral Neuroscience Branch, spoke about relapse to cocaine use after prolonged abstinence. His group showed that cocaine-seeking in rats progressively increased over the months after withdrawal from cocaine when they were prompted by cues they associated with the drug. In other words, their drug craving "incubates" over time. The same applies to heroin and methamphetamines. If this rat model reflects what humans experience, he explained, drug addicts may be highly vulnerable to relapse after periods of abstinence if they're exposed to cues they associate with abused drugs.

Shaham discussed the role of specific proteins in the central amygdala in this relapse process and described some promising attempts to block it. He also spoke about how stress is a major contributor to relapse. Pharmacological treatments look particularly promising for preventing stress-induced relapse.

Shaham pointed out that, for people who are dieting, stress can also provoke a relapse to bad eating habits. Last year, his team set about developing an animal model to look at compulsive food-seeking habits. They found that rats showed stress-induced food-seeking behavior similar to that for abused drugs. One promising treatment for stress-induced drug relapse also helped with stress-induced food-seeking in the animals. These types of animal models, which have led to experimental treatments for drug addiction in humans, promise to advance the field of food addiction as well.

Shaham's talk showed how work in one field (drug abuse) can unexpectedly yield important insights in another (eating habits). Students attending both these talks would also have gotten an excellent lesson in how completely different approaches to a problem — in this case, obesity — can both produce important results.