Participation of cyclooxygenase and PGs E2 and F2alfa during the development of the rat in the contractile effect of phenylephrine in rat aorta and coronary artery

Abstract

The aim of this paper is to analyze the changes of cyclooxygenase (COX) and prostaglandins (PGs) E2 and F2alfa involvement in the contractile response to phenylephrine in the thoracic and abdominal aorta and coronary artery of prepubertal young and old rats. It has been describe that during development there are changes in the activity of some enzymatic pathways, in this work we analyze the change in the involvement of cyclooxygenase and PGs in the contractile effect of phenylephrine with age. COX 1 and 2 have been related in the release of prostanoids that regulate the effect of various agonists as in the case of phenylephrine, but its unknown that how this enzyme is involved during the development of the rat cardiovascular level. In this experimental model we used male rats of 6, 16 weeks and 1 year of age. Rats were anesthetized with pentobarbital (50 mg/kg), after that we proceeded to obtain the thoracic aorta and abdominal aorta and the heart. The aortic rings were placed in an isolated organ system which keeps the tissue in physiological Krebs solution at a temperature of 37 ° C and bubbled with carbogen (95% O2 and 5% CO2) and the other hand the heart were placed in a Langendorf system. Then we proceeded to make concentration response curves to phenylephrine (10–9 to 10–5M) in the presence and absence of indomethacin, NS 398 and Sc560 (COX antagonist). We obtain 20mg of either heart, thoracic or abdominal aorta for the western blot analysis of COX 1 and COX 2 and for the PGS measurement. Results showed differences in participation of this enzyme and PGs in the contractile response to phenylephrine age‐dependent rat.