title: Co-administration of Apelin and T4 protects inotropic and chronotropic changes occurring in hypothyroid rats.
abstract: BACKGROUND
  One of the most important thyroid hormone targets is the cardiovascular system. Hemodynamic changes, such as decreased resting heart rate (HR), myocardial contractility, and cardiac output, and increased diastolic pressure and systemic vascular resistance, have been observed in hypothyroid patients. Moreover, in these patients, ECG changes include sinus bradycardia and low voltage complexes (P waves or QRS complexes).
  
  
  OBJECTIVE
  This study aimed at evaluating the prophylactic effect of apelin on HR changes and QRS voltage that occur in propylthiouracil (PTU)-induced hypothyroid rats.
  
  
  METHODS
  In this study, 48 adult male Wistar rats weighing 170-235g were randomly divided into 6 groups: Control group (normal saline ip injection + tap water gavage); P group (PTU 0.05%, in drinking water); A group (apelin 200 µg.kg-1.day-1, ip); PA group [co-administration of PTU and apelin]; PT group [co-administration of PTU + T4 (0.2 mg/g per day, gavage)]; and PAT group (co-administration of PTU, apelin and T4). All experiments were performed for 28 consecutive days, and then the animals were anesthetized with an ip injection of ketamine (80 mg/kg) and xylazine (12 mg/kg). Lead II electrocardiogram was recorded to calculate HR and QRS voltage.
  
  
  RESULTS
  Heart rate and QRS voltage increased more significantly in the hypothyroid group that consumed both apelin and T4 (201 ± 4 beat/min, 0.71 ± 0.02 mv vs. hypothyroid 145 ± 9 beat/min, 0.563 ± 0.015 mv; respectively).
  
  
  CONCLUSIONS
  The co-administration of apelin and T4 showed a protective effect on QRS voltage and HR in PTU‑induced hypothyroid rats.
authors.affiliation: Department of Physiology, Faculty of Medicine, Ahvaz Jundishapur University of Medical Sciences, Ahvaz, IR.
authors.forename: Zahra
authors.initials: Z
authors.lastname: Akhondali
authors.affiliation: Department of Physiology, Faculty of Medicine, Ahvaz Jundishapur University of Medical Sciences, Ahvaz, IR.
authors.forename: Mohammad
authors.initials: M
authors.lastname: Badavi
authors.affiliation: Department of Physiology, Faculty of Medicine, Ahvaz Jundishapur University of Medical Sciences, Ahvaz, IR.
authors.forename: Mahin
authors.initials: M
authors.lastname: Dianat
authors.affiliation: Department of Physiology, Faculty of Medicine, Ahvaz Jundishapur University of Medical Sciences, Ahvaz, IR.
authors.forename: Farzaneh
authors.initials: F
authors.lastname: Faraji
mesh_terms: D000818:Animals; D013956:Antithyroid Agents; D000073861:Apelin; D001835:Body Weight; D002316:Cardiotonic Agents / Q000008:administration & dosage*; D004338:Drug Combinations; D004562:Electrocardiography; D006339:Heart Rate / Q000187:drug effects*; D007037:Hypothyroidism / Q000139:chemically induced / Q000503:physiopathology*; D036341:Intercellular Signaling Peptides and Proteins / Q000008:administration & dosage*; D008297:Male; D009200:Myocardial Contraction / Q000187:drug effects*; D011441:Propylthiouracil; D011897:Random Allocation; D017208:Rats, Wistar; D015203:Reproducibility of Results; D013972:Thyrotropin / Q000097:blood; D013974:Thyroxine / Q000008:administration & dosage* / Q000097:blood
chemical_list: D013956:Antithyroid Agents; D000073861:Apelin; C498579:Apln protein, rat; D002316:Cardiotonic Agents; D004338:Drug Combinations; D036341:Intercellular Signaling Peptides and Proteins; D011441:Propylthiouracil; D013972:Thyrotropin; D013974:Thyroxine