Mechanism of Oxygen Induced Contraction of Ductus Arteriosus
The ductus arteriosus is a wide muscular artery that connects the aorta and pulmonary artery allowing blood ejected by the right ventricle to by-pass the non-functional pulmonary bed in utero. Shortly after birth, the ductus constricts due to the contraction of its smooth muscle. Numerous investigators (1,2,3,4) have drawn attention to the postnatal increase in arterial oxygen pressure as a stimulus for muscular closure of the ductus arteriosus. Although other agents may act to constrict the vessel in vivo(1,3,5,6,7,8) increased oxygen pressure appears to be the major factor responsible for closure of the ductus at birth. The studies described here represent an attempt to understand the mechanism underlying the constrictor effect of oxygen on this blood vessel. All of the studies have been performed on the ductus arteriosus of the neonatal guinea pig mounted for isometric measurement of force in an organ bath.
KeywordsOxygen Pressure Contractile Response Muscle Tension Organ Bath Polygraph Record
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