title: Effect of acute exercise on cardiovascular hemodynamic and red blood cell concentrations of purine nucleotides in hypertensive compared with normotensives rats.
abstract: OBJECTIVE
  The mechanisms of exercise-induced health benefits are complex and not fully understood. This study investigated the effects of exercise and hypertension on cardiovascular hemodynamic responses and red blood cell (RBC) concentrations of purine nucleotides using normotensive and hypertensive rat models in vivo.
  
  
  METHODS
  Sprague Dawley rats (SDRs) and spontaneously hypertensive rats (SHRs) were exercised on a treadmill for 15 min at a speed of 10 m/min and 5% grade. Blood samples were obtained from each rat before, during, and after exercise for measurement of adenosine 5'-triphosphate (ATP) and guanosine 5'-triphosphate (GTP) concentrations in RBCs by a validated high-performance liquid chromatography assay. They were returned to a restrainer after exercise, and hemodynamic recording collected continuously up to 6 h. Two separate groups (SDRs and SHRs) without exercise were used as controls. Biomarker data were compared between SDRs and SHRs using analysis of variance and t test and difference considered significant at p < 0.05.
  
  
  RESULTS
  The study has demonstrated for the first time a difference in the postexercise effect between SDRs and SHRs. The 15 min of exercise significantly increased systolic blood pressure (SBP) (129 ± 16 to 162 ± 26 mmHg) and heart rate (HR) (416 ± 29 to 491 ± 26 bpm) in SDRs (p < 0.05), but not in SHRs. The postexercise hemodynamic effects were more profound in SHRs. SBP and diastolic blood pressure (DBP) also fell significantly in the control group of SHRs (SBP 184 ± 14 to 152 ± 29 mmHg and DBP 149 ± 9 to 120 ± 14 mmHg, p < 0.05 for both) towards the end of the experiment but not in the SDR group. The RBC concentrations of ATP and GTP increased after exercise in both SDRs and SHRs which were significantly correlated with the postexercise hemodynamic effect (p < 0.05).
  
  
  CONCLUSIONS
  SHRs were more tolerant to increases in HR and SBP induced by exercise, and have more profound postexercise hemodynamic effects than SDRs. The hemodynamic effects were linked closely with RBC concentrations of ATP and GTP in both SDRs and SHRs.
authors: College of Pharmacy, Dalhousie University, Halifax, NS, Canada. pollen.yeung@dal.ca
authors: Pollen K F
authors: PK
authors: Yeung
authors: Julie
authors: J
authors: Dauphinee
authors: Tanya
authors: T
authors: Marcoux
mesh_terms: D000222:Adaptation, Physiological; D000255:Adenosine Triphosphate / Q000097:blood*; D000818:Animals; D001794:Blood Pressure; D002851:Chromatography, High Pressure Liquid; D004195:Disease Models, Animal; D004912:Erythrocytes / Q000378:metabolism*; D005080:Exercise Test; D006160:Guanosine Triphosphate / Q000097:blood*; D006339:Heart Rate; D006439:Hemodynamics; D006973:Hypertension / Q000097:blood* / Q000503:physiopathology*; D008297:Male; D005082:Physical Exertion; D051381:Rats; D011918:Rats, Inbred SHR; D017207:Rats, Sprague-Dawley; D013997:Time Factors; D015854:Up-Regulation
chemical_list: D006160:Guanosine Triphosphate; D000255:Adenosine Triphosphate