title: The effect of exercise on the total water space and red blood cell volume of the gracilis muscle of the dog.
abstract: The effect of increasing intensities of exercise on the water space and the red blood cell volume of the dog gracilis muscle was determined with 125I-labelled iodoantipyrine (n = 8) and 99mTc labelled red blood cells (n = 4). A sodium iodide scintillation probe attached to a two channel multiscaler and printer recorded the 125I activity of the muscle as a measure of the water space and the 99mTc activity as a measure of the red cell space. An electro-magnetic flow probe recorded muscle blood flow: aortic pressure was measured with a catheter in the mid-abdominal aorta. At least 30 min after i.v. administration of iodoantipyrine and red blood cells, the obturator nerve was electrically stimulated to produce muscle contraction at 1 contraction per second for 5 min. Data were recorded prior to exercise, during the 5 min exercise period, and for 10 min after exercise. During the greatest exercise period there was an eightfold increase in muscle blood flow, but only a small increase in [125I]iodoantipyrine activity (2.7 +/- 0.8%, 95% confidence limits) and 99mTc red blood cell activity (3.2 +/- 2.1%). Both values promptly returned to baseline during recovery. These data show that there is a minimal change in the water space and blood volume of the exercising dog gracilis muscle.
mesh_terms: D000818:Animals; D000983:Antipyrine / Q000031:analogs & derivatives; D001794:Blood Pressure; D001834:Body Water / Q000032:analysis*; D004285:Dogs; D004912:Erythrocytes / Q000166:cytology*; D007457:Iodine Radioisotopes; D009132:Muscles / Q000098:blood supply / Q000502:physiology*; D009929:Organ Size; D005082:Physical Exertion; D013667:Technetium
chemical_list: D007457:Iodine Radioisotopes; D013667:Technetium; D000983:Antipyrine; C008135:iodoantipyrine