THERMOSTAT FOR SLUMBER?
Optogenetics Pioneer Reports Progress on Deciphering Sleep

NIH director Dr. Francis Collins (r), alongside
Oxford’s Dr. Gero Miesenböck talks about configuring the brain for sleep.

Researchers have wondered for decades why and how we fall asleep. To solve several age-old questions about slumber, investigators are using a relatively young scientific technique—optogenetics—to study fruit flies hooked to treadmills.

“Sleep is one of the great biological mysteries— each night we disconnect ourselves from the world for 7 or 8 hours, a state that leaves us vulnerable and unproductive,” explained Oxford’s Dr. Gero Miesenböck in an NIH Neuroscience Seminar Series lecture held recently. “Despite these risks and costs, we do not know what sleep is good for.”

Miesenböck pioneered optogenetics, a technique scientists can use to manipulate nerve cells—neurons—that have been genetically altered to be sensitive to light. In 2010, the technique was named “Method of the Year” by journals across scientific disciplines and Science magazine called it “Breakthrough of the Decade.”

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Excess Growth Hormone Increases Risk of Heart Disease, Diabetes

Dr. Andrew Demidowich
Dr. Andrew Demidowich

Diseases of excess growth hormone, such as gigantism and acromegaly, may initially present with a variety of signs and symptoms, including diabetes, said Dr. Andrew Demidowich during a recent Grand Rounds lecture in Lipsett Amphitheater.

“The terms gigantism and acromegaly get thrown around together, but they’re not equivalent; they’re a little different,” explained Demidowich, an assistant research clinician in the Office of the Clinical Director at NICHD. He went on to clarify that gigantism results when excess growth hormone is produced before the growth plates of long bones (e.g., arms and legs) close. Consequently, people with gigantism are very tall.

In acromegaly, conversely, the growth excess begins after puberty, when the growth plates have already closed. As a result, those with acromegaly may have large skulls, jaws, nose, ears, palms and feet, but not the extremely tall height seen in gigantism.

Demidowich said the pituitary gland produces growth hormone after it receives a signal from the hypothalamus. Normally, the hormone stimulates bone and muscle growth, cell reproduction and regeneration. The hormone “isn’t secreted constantly, but rather comes in pulses or bursts,” especially when we sleep.

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