PRESS-NEWS.org - Press Release Distribution
PRESS RELEASES DISTRIBUTION

Mice can inherit learned sensitivity to a smell

2013-12-02
(Press-News.org) Contact information: Quinn Eastman
qeastma@emory.edu
404-727-7829
Emory Health Sciences
Mice can inherit learned sensitivity to a smell

Trauma can scar people so indelibly that their children are affected. History provides examples of generations traumatized by war and starvation, whose children experience altered physiology.

Now researchers at Yerkes National Primate Research Center, Emory University have found an instance of animals passing on more specific information about a traumatic experience to their offspring. That information comes not through social communication, but through inheritance.

Researchers have found that when a mouse learns to become afraid of a certain odor, his or her pups will be more sensitive to that odor, even though the pups have never encountered it.

The results were published online Dec. 1, 2013 in Nature Neuroscience.

"Knowing how the experiences of parents influence their descendants helps us to understand psychiatric disorders that may have a trans-generational basis, and possibly to design therapeutic strategies," says senior author Kerry Ressler, MD, PhD, professor of psychiatry and behavioral sciences at Emory School of Medicine.

Ressler is a Howard Hughes Medical Institute-supported investigator at Yerkes National Primate Research Center, Emory University. The first author of the paper is postdoctoral fellow Brian Dias, PhD.

Dias and Ressler trained mice to become afraid of an odor, by pairing exposure to the odor with a mild electric shock. They then measured how much the animal startled in response to a loud noise at baseline, and in conjunction with presentation of the odor.

Surprisingly, they found that the naïve adult offspring of the sensitized mice also startled more in response to the particular odor that one parent had learned to fear. In addition, they were more able to detect small amounts of that particular odor. Smell-sensitized offspring were not more anxious in general; Dias found that they were not more afraid to explore the exposed areas of a maze.

Dias and Ressler took advantage of previous research on the biology of odor detection. Scientists knew that the chemical acetophenone activates a particular set of cells in the nose and a particular "odorant receptor" gene in those cells. [Acetophenone smells somewhat like cherry blossom.]

Both a father mouse who has been sensitized to a smell and his pups have more space in the smell-processing part of their brains, called the olfactory bulb, devoted to the odor to which they are sensitive (see figure).

Dias found that both mothers and fathers can pass on a learned sensitivity to an odor, although mothers can't do it with fostered pups, showing that the sensitivity is not transmitted by social interaction. Future mothers receive their odor-shock training before (and not during) conception and pregnancy.

The inheritance takes place even if the mice are conceived by in vitro fertilization, and the sensitivity even appears in the second generation (grandchildren). This indicates that somehow, information about the experience connected with the odor is being transmitted via the sperm or eggs.

Dias discovered that the DNA from the sperm of smell-sensitized father mice is altered. This is an example of an "epigenetic" alteration: transmitted not in the letter-by-letter sequence of the DNA, but in its packaging or chemical modifications.

In mice taught to fear acetophenone, the odorant receptor gene that responds to acetophenone has a changed pattern of methylation: a chemical modification of DNA that tunes the activity of genes. However, it's not clear whether the changes in that gene are enough to make the difference in an animal's odor sensitivity.

"While the sequence of the gene encoding the receptor that responds to the odor is unchanged, the way that gene is regulated may be affected," Ressler says. "There is some evidence that some of the generalized effects of diet and hormone changes, as well as trauma, can be transmitted epigenetically. The difference here is that the odor-sensitivity-learning process is affecting the nervous system – and apparently, reproductive cells too -- in such a specific way."

What the researchers don't know yet:

Are these effects reversible – if sensitized parents later learn not to be afraid of an odor, will effects still be seen in their pups?

Does it only happen with odors? Could mice trained to be afraid of a particular sound, for example, pass on a sensitivity to that sound?

Do all the sperm or egg cells bear epigenetic marks conveying odor sensitivity?

How does information about odor exposure reach the sperm or eggs?

"We are really just scratching the surface at this point," Dias says. "Our next goal must be to buffer descendant generations from these effects, Such interventions could form the core of a treatment to prevent the development of neuropsychiatric disorders with roots in ancestral trauma."



INFORMATION:



The research was supported by the Howard Hughes Medical Institute and the Burroughs Wellcome Fund.



ELSE PRESS RELEASES FROM THIS DATE:

Forget the needle consider the haystack

2013-12-02
Forget the needle consider the haystack Uncovering hidden structures in massive data collections Advances in computer storage have created collections of data so huge that researchers often have trouble uncovering critical patterns in connections ...

Living with chronic pain: The daily struggle with a 'new self'

2013-12-02
Living with chronic pain: The daily struggle with a 'new self' People who suffer with chronic musculoskeletal pain face a daily struggle with their sense of self and find it difficult to prove the legitimacy of their condition. A new study, funded by the National Institute ...

Oxygen levels increase and decrease the effectiveness of anti-inflammatory therapies

2013-12-02
Oxygen levels increase and decrease the effectiveness of anti-inflammatory therapies New research published in the Journal of Leukocyte Biology suggests that the effectiveness of anti-inflammatory glucocorticoids may be related to ...

Understanding hearing

2013-12-02
Understanding hearing Computer models of neuronal sound processing in the brain lead to cochlear implant improvements This news release is available in German. Intact hearing is a prerequisite for learning to speak. This is why children ...

Newly discovered human peptide may become a new treatment for diabetes

2013-12-02
Newly discovered human peptide may become a new treatment for diabetes New research in The FASEB Journal suggests that humanin, a peptide produced by the human body, increases the metabolism of glucose in beta cells, which in turn ...

Salk scientists crack riddle of important drug target

2013-12-02
Salk scientists crack riddle of important drug target New method for determining structure of key cellular receptors could speed drug development LA JOLLA, CA---- A new approach to mapping how proteins interact with each other, developed at the Salk Institute for Biological Studies, ...

Difficult dance steps: Team learns how membrane transporter moves

2013-12-02
Difficult dance steps: Team learns how membrane transporter moves CHAMPAIGN, Ill. — Researchers have tried for decades to understand the undulations and gyrations that allow transport proteins to shuttle molecules from one side of a cell membrane ...

Head out to the ski slopes, for happiness' sake

2013-12-02
Head out to the ski slopes, for happiness' sake Study says even 1-off skiing trips can give you a valuable boost in pleasure and well-being Are you contemplating a skiing holiday? The all-out pleasure and enjoyment you experience on a pair of skis or a snowboard is positively ...

Process holds promise for production of synthetic gasoline

2013-12-02
Process holds promise for production of synthetic gasoline A chemical system developed by researchers at the University of Illinois at Chicago can efficiently perform the first step in the process of creating syngas, gasoline and other energy-rich products ...

Scientists discover that short-term energy deficits increase factors related to muscle degradation

2013-12-02
Scientists discover that short-term energy deficits increase factors related to muscle degradation New research in The FASEB Journal suggests that a high protein diet suppresses protein breakdown by slowing the activity of the ubiquitin ...

LAST 30 PRESS RELEASES:

Breathable yet protective: Next-gen medical textiles with micro/nano networks

Frequency-engineered MXene supercapacitors enable efficient pulse charging in TENG–SC hybrid systems

Developed an AI-based classification system for facial pigmented lesions

Achieving 20% efficiency in halogen-free organic solar cells via isomeric additive-mediated sequential processing

New book Terraglossia reclaims language, Country and culture

The most effective diabetes drugs don't reach enough patients yet

Breast cancer risk in younger women may be influenced by hormone therapy

Strategies for staying smoke-free after rehab

Commentary questions the potential benefit of levothyroxine treatment of mild hypothyroidism during pregnancy

Study projects over 14 million preventable deaths by 2030 if USAID defunding continues

New study reveals 33% gap in transplant access for UK’s poorest children

Dysregulated epigenetic memory in early embryos offers new clues to the inheritance of polycystic ovary syndrome (PCOS)

IVF and IUI pregnancy rates remain stable across Europe, despite an increasing uptake of single embryo transfer

It takes a village: Chimpanzee babies do better when their moms have social connections

From lab to market: how renewable polymers could transform medicine

Striking increase in obesity observed among youth between 2011 and 2023

No evidence that medications trigger microscopic colitis in older adults

NYUAD researchers find link between brain growth and mental health disorders

Aging-related inflammation is not universal across human populations, new study finds

University of Oregon to create national children’s mental health center with $11 million federal grant

Rare achievement: UTA undergrad publishes research

Fact or fiction? The ADHD info dilemma

Genetic ancestry linked to risk of severe dengue

Genomes reveal the Norwegian lemming as one of the youngest mammal species

Early birds get the burn: Monash study finds early bedtimes associated with more physical activity

Groundbreaking analysis provides day-by-day insight into prehistoric plankton’s capacity for change

Southern Ocean saltier, hotter and losing ice fast as decades-long trend unexpectedly reverses

Human fishing reshaped Caribbean reef food webs, 7000-year old exposed fossilized reefs reveal

Killer whales, kind gestures: Orcas offer food to humans in the wild

Hurricane ecology research reveals critical vulnerabilities of coastal ecosystems

[Press-News.org] Mice can inherit learned sensitivity to a smell