title: The relationship between the transverse and longitudinal nuclear magnetic resonance relaxation rates of muscle water.
abstract: Whole frog sartorius and gastrocnemius muscles were incubated in Ringer's solutions, either unenriched or enriched with H2 17Oor 2D2O. Subsequently, the rates of transverse (1/T2) and of longitudinal (1/T1) nuclear magnetic relaxation were measured for 17O, 2D, and 1H at room temperature and at 8.1 MHz. The ratio (T1/T2) for 17O was measured to be approximately 1.5-2.0, close to the value roughly estimated from the Larmor frequency dependence of 1/T1 alone over the range 4.3-8.1 MHz. On the other hand (T1/T2) for 2D and 1H were both measured to lie in the range 9-11. Insofar as the entire 17O signal was detected, the data indicate the presence of an exchange mechanism between the major fraction of intracellular water and a minor fraction characterized by enhanced rates of relaxation. Possible molecular mechanisms are presented.
mesh_terms: D000818:Animals; D001001:Anura; D055598:Chemical Phenomena; D002627:Chemistry, Physical; D003903:Deuterium; D066298:In Vitro Techniques; D009682:Magnetic Resonance Spectroscopy; D009124:Muscle Proteins; D009132:Muscles / Q000502:physiology*; D011893:Rana esculenta; D014867:Water
chemical_list: D009124:Muscle Proteins; D014867:Water; D003903:Deuterium