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
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.