title: A comparison of two anesthetic techniques for the study of rat skeletal muscle high-energy phosphates in vivo using 31P-NMR.
abstract: 31P-Nuclear magnetic resonance (NMR) spectroscopy was used to evaluate in vivo rat quadriceps ATP, phosphocreatine (PCr), inorganic phosphate (Pi) and tissue pH during anesthesia with ketamine/xylazine (K/X) or isoflurane (IS). A surface coil was used to receive signals from the quadriceps muscle of rats positioned in a wide-bore horizontal magnet. The PCr/beta-ATP ratios determined from the NMR spectra were 4.34 +/- 0.19 (K/X) and 4.40 +/- 0.28 (IS). Tissue pH was 7.09 +/- 0.05 (K/X) and 7.13 +/- 0.07 (IS). Metabolic stability of quadriceps PCr and ATP was demonstrated during both K/X and IS anesthesia, but the K/X-anesthetized animals had longer sleep time, lower food consumption, and lower body weight post-anesthesia than the IS-anesthetized animals. The PCr/beta-ATP ratio in quadriceps of repetitively IS-anesthetized rats did not fluctuate diurnally. In addition, the animals recovered rapidly and continued to gain weight following the multiple brief IS anesthetic procedures. These data indicate that serial in vivo investigations of high-energy-phosphate metabolism in small animals can be accomplished using 31P-NMR spectroscopy and IS anesthesia, which has several advantages over K/X anesthesia for these types of studies.
authors.affiliation: Department of Internal Medicine, University of California School of Medicine, Davis 95616.
authors.forename: S F
authors.initials: SF
authors.lastname: Loy
authors.forename: W A
authors.initials: WA
authors.lastname: Boyle
authors.forename: L D
authors.initials: LD
authors.lastname: Segel
mesh_terms: D000227:Adenine Nucleotides / Q000378:metabolism*; D000777:Anesthetics / Q000494:pharmacology*; D000818:Animals; D001835:Body Weight / Q000187:drug effects; D002940:Circadian Rhythm / Q000187:drug effects; D004435:Eating / Q000187:drug effects; D004734:Energy Metabolism; D007530:Isoflurane / Q000494:pharmacology; D007649:Ketamine / Q000494:pharmacology; D009682:Magnetic Resonance Spectroscopy; D009132:Muscles / Q000378:metabolism*; D010725:Phosphocreatine / Q000378:metabolism*; D051381:Rats; D014991:Xylazine / Q000494:pharmacology
chemical_list: D000227:Adenine Nucleotides; D000777:Anesthetics; D010725:Phosphocreatine; D014991:Xylazine; D007649:Ketamine; D007530:Isoflurane