Changes in diaphragm polyinositol phosphates caused by a large body surface area burn.

Respiratory problems are common among burn patients, and an understanding of the changes that occur in the phosphatidyl inositol signal transducing system (s.t.s.) in diaphragm muscle may identify pharmacological agents that would be useful in the treatment of these patients. This report examines changes that occur in polyinositol phosphates of diaphragm muscle due to the systemic effects of large (> 30 per cent) body surface area (per cent BSA) burns. Burn injury was applied to specific per cent BSA of the dorsal and ventral skin surfaces of mice. At postburn day 21, polyinositol phosphate levels were measured in the diaphragm by the incorporation of myo-[2-3H]inositol with separation of the phosphates by anion-exchange chromatography. All data were analysed using analysis of variance and curve fitting. In the diaphragm, levels of [3H]inositol, inositol-1,4,5 trisphosphate (IP3), inositol-1,4 bisphosphate (I1,4P2) and inositol-1 phosphate (I1P) increased with increasing burn size. Furthermore, a variety of independent relationships existed between the various phosphates in each burn group (i.e. control, 20 per cent and 50 per cent BSA burn). These data indicate that the systemic effects of burn trauma result in changes in the polyinositol phosphate part of the phosphatidyl inositol signal transducing system of diaphragm muscle.