Effects of Melatonin Administration on Vasomotor Activity and Histological Structure of Isolated Thoracic Aorta in Rats Treated with Thyroxine

Objective: The goal of this study was to examine the effect in vivo melatonin (MEL) administration on isolated thoracic aorta rats with thyroxine treatment and its duty aortic response contractile agents, such as potassium chloride (KCl) phenylephrine (PE). In addition, immunohistological alterations were also examined.
 Methods: Experimental groups follows: control group (n= 5), 6), + 6). L-thyroxine given by intraperitoneal (i.p) at 0.3 mg/kg/day for 14 days. MEL administered i.p., 3 from euthanized cervical dislocation. Then, vascular rings prepared.
 Concentration-response curves KCl PE applications recorded an organ bath. Tissue samples fixed 10% formalin histopathological evaluation.
 Results: PE-induced contractions reduced significantly thyroxine-treated rats. partially attenuated reduction contraction responses due treatment. Immunohistological findings showed that inhibits thickening vessel wall probably suppressing collagen formation tissue.
 Conclusion: Our results suggest may attenuate decrease resistance caused