Systolic blood pressure during the formation of a social dominance hierarchy in C57BL/6j mice.

Housing male mice in social groups typically results in social dominance hierarchies and elevated systolic blood pressures. An exception to this pattern occurs in the C57BL/6j inbred mouse strain. C57BL/6j male mice, when handled prior to the experiment, tend to display neither social dominance hierarchies nor systolic hypertension. In the present experiment, we found that when C57BL/6j males compete for social dominance, as indicated by wounding, they also show elevations in systolic pressure. The association of social hierarchy and systolic pressure elevation can be found not only in aggressive mouse strains, but also within the more pacific C57BL/6j strain when it is exposed to competition.