Muneki Ohuchi

Effects of l- and d-propranolol on the ischemic myocardial metabolism of the isolated guniea pig heart, as studied by 31P-NMR.

Summary Using 31P nuclear magnetic resonance (NMR) spectroscopy (acquisition time of 3 min). we studied the effects of l- and d-propranolol on the ischemic derangement of myocardial energy metabolism in the isolated perfused guinea pig heart. The myocardial pH and concentration of high-energy phosphate were used as measures of the energy metabolism. Cardiac pH progressively declined during ischemia from 7.41 ± 0.04 to 7.13 ± 0.05, 6.91 ± 0.04, 6.74 ± 0.04, and 6.61 ± 0.04 (before ischemia and 3, 6, 9, and 12 min after ischemia, respectively). After 3 min of reperfusion, pH rapidly returned to 7.42 ± 0.04. Creatine phosphate (CP) and adenosine triphosphate (ATP) contents were reduced, while inorganic phosphate (Pi) contents were increased during ischemia. Whereas CP and Pi contents were restored to the normal values after reperfusion, the recovery of ATP contents was poor. Both l- and d-propranolol (10-6M) significantly suppressed the fall of the myocardial pH. Changes in the high-energy phosphate contents were also attenuated by l- and d-propranolol. These results suggest that not only l-propranolol, but also d-propranolol can produce beneficial effects on the ischemic derangements of myocardial energy metabolism.

Spin-lattice relaxation of carbon-13 in the rotating frame

Abstract Measurements of T 1 ϱ on 13 C are performed by Fourier transform NMR with proton decoupling, and origins of systematic errors in the T 1 ϱ experiment are discussed in detail. Measurements on cis-decalin and chlorinated compounds are carried out to confirm the accuracy of T 1 ϱ values of 13 C under proton decoupling. The estimated value of chemical shift difference between the two chemical-exchange sites of cis -decalin by the T 1 ϱ experiment shows good agreement with the value from direct measurement at low temperature (−30°C). The activation energy of fast molecular motion for T 1 processes is estimated, as well as that of slow motion for T 1 ϱ , and the exchange rate of the two sites is calculated. For several chlorinated compounds, the scalar coupling constants J ccl and T 1 of the chlorine are estimated.