title: Adenosine output from dog gracilis muscle during systemic hypercapnia and/or amiloride-SITS infusion.
abstract: The influence of acidosis on adenosine output from the isolated constant-flow-perfused gracilis muscle was studied in anesthetized dogs. Depression of intracellular pH (pHi) by supplementation of the inspired air with 10% CO2-90% O2 increased arterial PCO2 from 34.2 +/- 1.0 to 53.5 +/- 1.9 mmHg, arterial PO2 from 138.3 +/- 3.9 to 256.6 +/- 17.6 mmHg, and venoarterial adenosine concentration from 14 +/- 15 to 47 +/- 19 nM. Twitch contractions of the muscle at 2 Hz increased venoarterial adenosine concentration to 165 +/- 63 and 204 +/- 62 nM in normocapnia and hypercapnia, respectively. Venoarterial lactate concentration increased from 0.42 +/- 0.07 to 0.90 +/- 0.15 mM during normocapnic contractions but remained unchanged during hypercapnic contractions (0.42 +/- 0.11 mM). Depression of pHi by infusion of amiloride and 4-acetamido-4'-isothiocyanostilbene-2,2'-disulfonic acid increased venoarterial adenosine concentration from -2 +/- 27 to 124 +/- 48 nM in normocapnia and from 16 +/- 24 to 236 +/- 119 nM in hypercapnia. These results indicate that adenosine output from red oxidative skeletal muscle was stimulated by procedures that depress pHi.
authors.affiliation: Department of Physiology, University of Hong Kong.
authors.forename: F M
authors.initials: FM
authors.lastname: Mo
authors.forename: H J
authors.initials: HJ
authors.lastname: Ballard
mesh_terms: D012856:4-Acetamido-4'-isothiocyanatostilbene-2,2'-disulfonic Acid / Q000008:administration & dosage / Q000494:pharmacology*; D000241:Adenosine / Q000378:metabolism*; D000584:Amiloride / Q000008:administration & dosage / Q000494:pharmacology*; D000818:Animals; D002245:Carbon Dioxide / Q000097:blood*; D004285:Dogs; D004558:Electric Stimulation; D006400:Hematocrit; D066298:In Vitro Techniques; D007261:Infusions, Intra-Arterial; D007537:Isometric Contraction; D009132:Muscles / Q000098:blood supply / Q000187:drug effects / Q000502:physiology*; D010100:Oxygen / Q000097:blood; D010313:Partial Pressure; D010477:Perfusion
chemical_list: D002245:Carbon Dioxide; D012856:4-Acetamido-4'-isothiocyanatostilbene-2,2'-disulfonic Acid; D000584:Amiloride; D000241:Adenosine; D010100:Oxygen