Mouse mothers-to-be have a remarkable way to protect their unborn pups. Because the smell of a strange male’s urine can cause miscarriage and reactivate the ovulatory cycle, pregnant mice prevent the action of such olfactory stimuli by blocking their smell.
Researchers from the European Molecular Biology Laboratory (EMBL) in Monterotondo, Italy, have now revealed the nature of this ability. A surge of the chemical signal dopamine in the main olfactory bulb - one of the key brain areas for olfactory perception – creates a barrier for male odours, they report in the current issue of Nature Neuroscience.
Social odours, such as pheromones, influence many aspects of human and animal behaviour – perhaps most widely known reproductive behaviour. For example, exposing a newly pregnant mouse to the smell of an alien male’s urine prevents the implantation of her embryos into the uterus and brings her back into the ovulatory cycle. The scent affects pregnancy by inhibiting the release of the pregnancy hormone prolactin.
his phenomenon is often called the Bruce effect and creates a mating opportunity for the alien male. It is also beneficial for the female because it avoids infanticide by the strange male after birth. After day 3 of pregnancy, however, the smell of an alien male’s urine no longer affects pregnancy. At this stage the embryos have already been implanted into the uterus and loosing them would bear a high cost for the female.
Liliana Minichiello and her team at the EMBL Mouse Biology Unit now discovered the molecular mechanism that underpins this change in sensitivity to male odours.
“At day 3 of the pregnancy a chemical change occurs in the brain of the expectant mother that makes her unable to perceive male odours. This seems to mark a point of no return for the pregnancy,” explains Minichiello.
Following coitus, a progressive surge of the chemical signal dopamine takes place in the main olfactory bulb, the most anterior part of the mouse brain that is dedicated to the processing of odours. The dopamine flood is triggered by the physical stimulation during mating and progressively impairs the perception and discrimination of social odours contained in male urine. Treating pregnant mice with chemicals that block the dopamine receptor D2 abolished the barrier effect, restored odour sensing and favoured pregnancy disruption.
The findings unexpectedly reveal the main olfactory bulb as a key control centre of social and reproductive behaviour. Previous research in this area had focussed almost exclusively on other brain circuits. The main olfactory bulb likely achieves its control through projections to the amygdala and the hypothalamus, those regions of the brain that regulate emotional and reproductive behaviour through the release of hormones.
Dopamine is also found in humans, where it is mostly known for its role as the brain’s ‘reward chemical’ that plays crucial roles in addiction and neurological disorders like Parkinson’s disease, but it is also found in the human olfactory bulb. It is unknown if a process similar to the phenomenon observed in mice takes place in pregnant women.
“As far as we know, human pregnancy is not affected by strange male odours, but it could help explain why many women report changes in olfaction during pregnancy,” says Che Serguera, who carried out the research in Minichiello’s lab.
Published online in Nature Neuroscience on 20 July 2008.
Anna-Lynn Wegener | EMBL
Hopkins researchers ID neurotransmitter that helps cancers progress
26.04.2019 | Johns Hopkins Medicine
Trigger region found for absence epileptic seizures
25.04.2019 | RIKEN
For the first time, physicists at the University of Basel have succeeded in measuring the magnetic properties of atomically thin van der Waals materials on the nanoscale. They used diamond quantum sensors to determine the strength of the magnetization of individual atomic layers of the material chromium triiodide. In addition, they found a long-sought explanation for the unusual magnetic properties of the material. The journal Science has published the findings.
The use of atomically thin, two-dimensional van der Waals materials promises innovations in numerous fields in science and technology. Scientists around the...
Flexible, organic and printed electronics conquer everyday life. The forecasts for growth promise increasing markets and opportunities for the industry. In Europe, top institutions and companies are engaged in research and further development of these technologies for tomorrow's markets and applications. However, access by SMEs is difficult. The European project SmartEEs - Smart Emerging Electronics Servicing works on the establishment of a European innovation network, which supports both the access to competences as well as the support of the enterprises with the assumption of innovations and the progress up to the commercialization.
It surrounds us and almost unconsciously accompanies us through everyday life - printed electronics. It starts with smart labels or RFID tags in clothing, we...
The human eye is particularly sensitive to green, but less sensitive to blue and red. Chemists led by Hubert Huppertz at the University of Innsbruck have now developed a new red phosphor whose light is well perceived by the eye. This increases the light yield of white LEDs by around one sixth, which can significantly improve the energy efficiency of lighting systems.
Light emitting diodes or LEDs are only able to produce light of a certain colour. However, white light can be created using different colour mixing processes.
Researchers led by Francesca Ferlaino from the University of Innsbruck and the Austrian Academy of Sciences report in Physical Review X on the observation of supersolid behavior in dipolar quantum gases of erbium and dysprosium. In the dysprosium gas these properties are unprecedentedly long-lived. This sets the stage for future investigations into the nature of this exotic phase of matter.
Supersolidity is a paradoxical state where the matter is both crystallized and superfluid. Predicted 50 years ago, such a counter-intuitive phase, featuring...
A stellar flare 10 times more powerful than anything seen on our sun has burst from an ultracool star almost the same size as Jupiter
17.04.2019 | Event News
15.04.2019 | Event News
09.04.2019 | Event News
26.04.2019 | Physics and Astronomy
26.04.2019 | Life Sciences
26.04.2019 | Physics and Astronomy