Just say NO (or yes?) to aggression.Two new studies of mice lacking enzymes that make nitric oxide nitric oxide or nitrogen monoxide, a colorless gas formed by the combustion of nitrogen and oxygen as given by the reaction: energy + N2 + O2 → 2NO; m.p. −163.6°C;; b.p. −151.8°C;. (NO) should help scientists better understand the role of the compound in regulating rodent aggression and perhaps clarify its influence on human behaviors. Once dismissed as a mere air pollutant, nitric oxide has proved to be a versatile molecule in the human body, providing services including the triggering of penile penile /pe·nile/ (pe´nil) of or pertaining to the penis. pe·nile adj. Of or relating to the penis. penile of or pertaining to the penis. erections and helping the immune system immune system Cells, cell products, organs, and structures of the body involved in the detection and destruction of foreign invaders, such as bacteria, viruses, and cancer cells. Immunity is based on the system's ability to launch a defense against such invaders. battle microbes. The compound also is one of the many molecular signals that enable brain cells to communicate. About 4 years ago, researchers created mice lacking the enzyme that synthesizes nitric oxide in nerve cells. Male mice of this mutant strain constantly attacked other males and kept trying to mate with females that had rejected them. This behavior, the investigators concluded, implied that the gas plays a part in the brain signals that dampen aggression. Although nitric oxide may make male mice mellow, it seems to act in the opposite manner in mother mice. Female mice are normally docile, except when they've just given birth. Then, they'll challenge strange males that approach their pups. Yet mothers from the mutant strain, deficient in nitric oxide, are much less vigorous at defending their pups, Stephen C. Gammie and Randy J. Nelson of Johns Hopkins University Johns Hopkins University, mainly at Baltimore, Md. Johns Hopkins in 1867 had a group of his associates incorporated as the trustees of a university and a hospital, endowing each with $3.5 million. Daniel C. in Baltimore report in the Sept. 15 JOURNAL OF NEUROSCIENCE The Journal of Neuroscience (Online ISSN 1529-2401) is a weekly scientific journal published by the Society for Neuroscience. The journal publishes peer-reviewed empirical research articles in the field of neuroscience. . The results suggest that nitric oxide is essential to brain signals for maternal aggression. "I didn't expect this outcome," says Gammie. The confusing interplay of nitric oxide and aggression doesn't end there. Gregory E. Demas of Georgia State University History Georgia State University was founded in 1913 as the Georgia School of Technology's "School of Commerce." The school focused on what was called "the new science of business. in Atlanta and his colleagues, including Gammie and Nelson, recently studied mice lacking a different enzyme that some cells, primarily in blood vessels Blood vessels Tubular channels for blood transport, of which there are three principal types: arteries, capillaries, and veins. Only the larger arteries and veins in the body bear distinct names. , use to make nitric oxide. Males of this strain are less aggressive than normal males, the researchers report in an article published online Sept. 16 by the JOURNAL OF NEUROSCIENCE. The behavioral shift was unexpected since the second enzyme isn't in nerve cells, says Gammie. Demas speculates that nitric oxide made by blood vessels in the brain may diffuse to nearby nerve cells, or the compound may dilate dilate /di·late/ (di´lat) to stretch an opening or hollow structure beyond its normal dimensions. di·late v. To make or become wider or larger. blood vessels and increase blood flow to brain regions involved in aggression. Scientists might resolve the role of nitric oxide in aggression by breeding the two mutant strains to make mice lacking both of the nitric oxide-making enzymes, says Demas. |
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