title: Cardiac adaptive mechanisms of Tibetan antelope (Pantholops hodgsonii) at high altitudes.
abstract: OBJECTIVE
  To identify cardiac mechanisms that contribute to adaptation to high altitudes in Tibetan antelope (Pantholops hodgsonii).
  
  
  METHODS
  9 male Tibetan antelope and 10 male Tibetan sheep (Ovis aries).
  
  
  METHODS
  Tibetan antelope and Tibetan sheep inhabiting a region with an altitude of 4,300 m were captured, and several cardiac variables were measured. Expression of genes for atrial natriuretic peptide, brain natriuretic peptide, and calcium-calmodulin-dependent protein kinase II δ was measured via real-time PCR assay.
  
  
  RESULTS
  Ratios of heart weight to body weight for Tibetan antelope were significantly greater than those of Tibetan sheep, but ratios of right-left ventricular weights were similar. Mean ± SD baseline heart rate (26.33 ± 6.15 beats/min) and systolic arterial blood pressure (97.75 ± 9.56 mm Hg) of antelope were significantly lower than those of sheep (34.20 ± 6.57 beats/min and 130.06 ± 17.79 mm Hg, respectively). The maximum rate of rise in ventricular pressure in antelope was similar to that in Tibetan sheep, but after exposure to air providing a fraction of inspired oxygen of 14.6% or 12.5% (ie, hypoxic conditions), the maximum rate of rise in ventricular pressure of the antelope increased significantly to 145.1% or 148.1%, respectively, whereas that of the sheep decreased to 68.4% or 70.5%, respectively. Gene expression of calcium-calmodulin-dependent protein kinase II δ and atrial natriuretic peptide, but not brain natriuretic peptide, in the left ventricle of the heart was significantly higher in antelope than in sheep.
  
  
  CONCLUSIONS
  Hearts of the Tibetan antelope in this study were well adapted to high-altitude hypoxia as shown by higher heart weight ratios, cardiac contractility in hypoxic conditions, and expression of key genes regulating cardiac contractility and cardiac hypertrophy, compared with values for Tibetan sheep.
authors.affiliation: Research Center for High Altitude Medicine, Qinghai University Medical College, Qinghai University, Xining 810001, China.
authors.forename: Chang
authors.initials: C
authors.lastname: Rong
authors.forename: Ma
authors.initials: M
authors.lastname: Yan
authors.forename: Bai
authors.initials: B
authors.lastname: Zhen-Zhong
authors.forename: Yang
authors.initials: Y
authors.lastname: Ying-Zhong
authors.forename: Lu
authors.initials: L
authors.lastname: Dian-Xiang
authors.forename: Ma
authors.initials: M
authors.lastname: Qi-Sheng
authors.forename: Ga
authors.initials: G
authors.lastname: Qing
authors.forename: Liu
authors.initials: L
authors.lastname: Yin
authors.forename: Ri-Li
authors.initials: RL
authors.lastname: Ge
mesh_terms: D000220:Adaptation, Biological / Q000502:physiology*; D000531:Altitude; D000818:Animals; D000866:Antelopes / Q000502:physiology*; D009320:Atrial Natriuretic Factor / Q000235:genetics / Q000378:metabolism; D001772:Blood Cell Count / Q000662:veterinary; D001835:Body Weight / Q000502:physiology; D054732:Calcium-Calmodulin-Dependent Protein Kinase Type 2 / Q000235:genetics / Q000378:metabolism; D006321:Heart / Q000033:anatomy & histology / Q000502:physiology*; D006454:Hemoglobins / Q000032:analysis; D008297:Male; D020097:Natriuretic Peptide, Brain / Q000235:genetics / Q000378:metabolism; D009929:Organ Size / Q000502:physiology; D060888:Real-Time Polymerase Chain Reaction / Q000662:veterinary; D012756:Sheep / Q000502:physiology*; D018609:Tibet; D017725:Ventricular Pressure / Q000502:physiology
chemical_list: D006454:Hemoglobins; D020097:Natriuretic Peptide, Brain; D009320:Atrial Natriuretic Factor; D054732:Calcium-Calmodulin-Dependent Protein Kinase Type 2