Perelman School of Medicine at the University of Pennsylvania researchers have discovered a mechanism involving the neurotransmitter dopamine that switches fruit fly behavior from being active during the day (diurnal) to nocturnal. This change parallels a human disorder in which increased agitation occurs in the evening hours near sunset and may also be due to higher than normal dopamine levels in the brain. Sundown syndrome occurs in older people with dementia or cognitive impairment.
- Medicine - 11:00 Alcohol sales fall due to ban on multi- buy promotions
- Astronomy - 10:30 Moonrise
- Environmental Sciences - 10:00 Shedding light on forests
- Pedagogy - 09:00 Parents should be allowed to make informed choices over infant bed- sharing, says child sleep expert
- Medicine - 08:00 Largest- ever global survey of 1,273 women in 12 countries reveals women with advanced breast cancer feel left out of the breast cancer movement
- Mechanical Engineering - 07:30 Crash risk among young drivers linked to less sleep
- Social Sciences - 07:30 Big miners’ community engagement doing more harm than good?
- Medicine - May 20 Discovery of a novel medicine for the treatment of chronic wounds
- Medicine - May 20 Penn Medicine Study Raises Questions About Added Costs and Physician Resources
- Event - May 20 Salil Vadhan named Simons Investigator
- Medicine - May 20 Vigorous athletic activity is safe with implanted arrhythmia devices
- Literature - May 20 Sarah Thomas to lead Harvard Library
- Medicine - May 20 No-treatment approach may be best choice for older prostate cancer patients
- Life Sciences - May 20 Amazon River exhales virtually all carbon taken up by rain forest
- Physics - May 20 Stanford physicists develop revolutionary low- power polariton laser
- Arts - May 20 The Golden Gate returns to Stanford May 30
Sundown Syndrome-like Symptoms in Fruit Flies May be Due to High Dopamine Levels
Many geriatricians have noted an association between sundown syndrome and changes in the internal biological clock among people with dementia, observing disruptions in their sleep-wake cycles. The internal clock, which guides rhythms over a 24-hour day, is connected to how active humans are at different times of the day.
The lab of Amita Sehgal, PhD , professor of Neuroscience and a Howard Hughes Medical Institute investigator, found that in fruit flies dopamine acts to arouse flies through a protein called cryptochrome that normally functions as a photoreceptor. Flies, like humans, are typically diurnal. The findings were released online this week in Genes & Development.
Using a strain of fly that has a mutated Clock (Clk) gene and exhibits nocturnal behavior, the team found that increased night-time activity of the Clk mutant flies is associated with elevated dopamine signaling. Specifically, Clk mutant flies have increased levels of an enzyme used to make dopamine called tyrosine hydroxylase in fly brains. The night-time behavior also requires the circadian photoreceptor, cryptochrome (CRY), in specific cells of the fly brain. These cells also express CLK, as do others that may be responsible for the elevated dopamine.
"Our results suggest that typically the dopamine pathway and CRY promote acute arousal. They allow an animal to respond to acute stimulation by sensory stimuli with a transient increase in activity," says Sehgal. "However, chronic, increased signaling of the pathway leads to nocturnal activity, most likely because both CRY and dopamine activity are dampened by light." A switched behavioral cycle is the result.
Click here to view the full release.
Last job offers
- Arts - 21.5
Wissenschaftliche/r Mitarbeiter/in (50%)
- Computer Science - 21.5
PhD Candidate in Healthcare Innovation Management
- Computer Science - 15.5
Computer Scientist specialized in Mobile Devices
- Pedagogy - 15.5
Doktorandin oder Doktorand
- Environmental Sciences - 14.5
PhD Position Agent-Based Modelling (13 TV-L, 50%)
- Business - 14.5
Wissenschaftliche/r Mitarbeiter/in Steuern
- Social Sciences - 20.5
Professor, Social Policy
- Pedagogy - 20.5
Senior Lecturer / associate Professor - Associate Director of Teaching and Learning
- Psychology - 17.5
Juniorprofessur (W1) für Sozialpsychologie
- Life Sciences - 17.5
Juniorprofessur für High Throughput Genomics
- Medicine - 20.5
Associate Professor / Lecturer in Biostatistics
- History - 17.5
Professor of Early Modern British History
- Medicine - 18.5
Assistant Professor, Health Policy 1
- Medicine - 18.5
Assistant Professor, Health Policy 2