How social isolation may increase stress
New York, May 18: Researchers have found that long term chronic isolation cause the build-up of a chemical in the brain, that increases stress, aggression and fear.
The mice isolated for two weeks showed behavioural changes like, increased aggressiveness towards unfamiliar mice, persistent fear, and hypersensitivity to threatening stimuli.
When encountering a threatening stimulus, mice that have been socially isolated remain frozen in place long after the threat has passed, whereas normal mice stop freezing soon after the threat is removed, the research said.
Although the study was done in mice, it has potential implications for understanding how chronic stress affects humans and has potential applications for treating mental health disorders, said lead author Moriel Zelikowsky, postdoctoral scholar at the California Institute of Technology in the US.
Previous studies have determined that social isolation for two weeks in mice resulted in the upregulation of the signalling molecule neuropeptide, tachykinin 2 (Tac2)/neurokinin B (NkB) -- a short protein molecule.
In the new study, published in the journal Cell, the team found that chronic isolation leads to an increase in Tac2 gene expression and the production of a neuropeptide called neurokinin B (NkB) throughout the brain.
But, administration of a drug that chemically blocks NkB-specific receptors enabled the stressed mice to behave normally, eliminating the negative effects of social isolation.
On the other hand, artificially increasing Tac2 levels and activating the corresponding neurons in normal, animals led them to behave like isolated and stressed, the research showed.
Suppressing the Tac2 gene in certain different brain parts, increased fear behaviours, or aggression accordingly, implying that it must increase in different brain regions to produce the various effects of social isolation, the researchers said.
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Rape accused's mother murdered by victim's brother in MP's Shivpuri
Shivpuri (PTI): The 60-year-old mother of a rape accused was killed allegedly by the victim's brother in Madhya Pradesh's Shivpuri district, a police official said on Saturday.
The incident took place on Friday, Rannod police station house officer (SHO) Arvind Chauhan said.
"An anganwadi worker returning from a hospital was offered a lift by one Inder Gurjar, who took her to a secluded spot and raped her. She called up her brothers to narrate the ordeal. One brother of the victim along with two associates went to Gurjar's house and assaulted him. When Gurjar's mother Sirkunwarbai (60) intervened, she was attacked with a sharp weapon. She died on the spot," he said.
Based on a complaint filed by the deceased woman's daughter-in-law, three persons were booked for murder. One of them was held on Saturday, the official added.
A separate case has also been registered against Gurjar for rape, he said.
Police personnel have been deployed in the area in view of tension following the incident, the official added.
