Calponin phosphorylation in cerebral cortex microvessels mediates sustained vasoconstriction after brain trauma.

OBJECTIVES

The purpose of this study was to determine the molecular and biochemical changes in the contractile protein, calponin (Cp), which temporally coincide with a previously reported state of sustained contractility following traumatic brain injury (TBI).

METHODS

Double immunofluorescence, western analysis and two-dimensional non-equilibrium pH gradient gel electrophoresis (NEPHGE)/SDS-PAGE techniques were utilized to determine both the location and extent of Cp within smooth muscle cells (SM) and the phosphorylation state of Cp following TBI, as induced using a weight drop acceleration impact model.

RESULTS

Double immunofluorescence for Cp and SM indicate that following injury, Cp migrates from the cytosol to a location subjacent to the SM membrane. Western analysis revealed a significant increase in Cp protein expression following injury that was maintained up to 48 hours post-injury. Combined Western analysis and NEPHGE indicated that Cp is phosphorylated following TBI.

DISCUSSION

Cp migration and phosphorylation may underlie the mechanism for increased vasoreactivity leading to hypoperfusion following TBI.