An NMR probe to study function and metabolism simultaneously in isolated human cardiac tissue

Trabeculae isolated from human atrial appendages have been used to study preservation of donor hearts for cardiac transplantation. We have developed a perifusion system equipped with a fiber optic strain gauge to study mechanical performance of human atrial trabeculae (10‐20 mg) while simultaneously observing the energetic compounds by 31 P NMR spectroscopy. The NMR probe consists of an eight‐turn solenoid coil (2.3 mm i. d. × 5 mm length, 24‐gauge wire) double tuned to allow observation of 1 H and 31 P nuclei. The probe and the perifusion system are temperature regulated and permit preservation studies using a variety of small muscles at low temperatures (down to 4°C) as well as at physiological temperature (37°C). 31 P NMR spectra suitable for quantification can be obtained from ≈ 10 mg of human atrial trabeculae in 15 min. Spectra of 8‐to 12‐mg mouse extensor digitalis longus or soleus muscle can be obtained in less than 10 min. © 1991 Academic Press, Inc.