The use of 31P-NMR to study smooth muscle.

The use of 31P NMR to study smooth muscle is hindered by low metabolite concentrations and low tissue mass. These disadvantages can be overcome due to low rates of energy utilization and the temporal stability of smooth muscle. Smooth muscle free Mg++, ADP, and the creatine analogue beta-guanidinopropionate can be studied in ways distinctive from 31P NMR of striated muscle. The pharmacological effects of naturally occurring agents such as insulin, glucose, or norepinephrine, and of NMR markers such as phenylphosphonate or 3-(trimethylsilyl)-1-propane-sulfonate on both vascular smooth muscle and perfused smooth muscles can be measured. Given sufficient collection time, 31P NMR is as useful in assessing the behavior of smooth muscle as it is of other muscle types.