Back
Acta Physiologica 2009; Volume 195, Supplement 667
XXXV Congress of The Spanish Society for Physiological Sciences
2/17/2009-2/20/2009
Valencia, Spain
ADRENERGIC STIMULATION INDUCES COX-2-DERIVED PROSTANOIDS RELEASE IN HUMAN GASTROEPIPLOIC ARTERY
Abstract number: P141
Cortina1 B, Vila1 JM, Juez1 M, Segarra1 G, Aldasoro1 M
1Departamento de Fisiologa. Universitat de Valencia. Blasco Ibez 17, 46010 Valencia, Spain. [email protected]
Aim:
Two COX isoforms (COX-1 and COX-2) are known. COX-1 is primarily responsible for the synthesis of thromboxane A2 (TXA2) whereas COX-2 is a major source of systemic prostacyclin (PGI2) biosynthesis in healthy humans. The possible intervention of COX-1 and COX-2 on adrenergic-mediated responses of human vessels is not fully known. The aim of the present study was to evaluate the intervention of COX-1 and COX-2-derived prostaglandins in the responses of human gastroepiploic artery to sympathetic stimulation and noradrenaline.
Methods:
Rings of human gastroepiploic artery were obtained from 45 patients (26 men and 19 women) undergoing gastrectomy. The rings were suspended in organ baths for isometric recording of tension. We studied the responses to electrical field stimulation (EFS, 2, 4 and 8 Hz, 15 V, 0.2 ms duration for 30s), noradrenaline and acetylcholine, in the absence and presence of COX-1 or COX-2 inhibition (aspirin, SC-560 or nimesulide).
Results:
The COX-1 and COX-2 inhibitor aspirin at high concentrations (10-6-10-5 M) and the COX-2 inhibitor nimesulide (10-6 M) potentiated the contractile responses of the arterial rings to sympathetic stimulation and induced a parallel leftward shift (about 6.3 and 8.4 times for aspirin and 3.1 times for nimesulide) of the concentration-response curve for noradrenaline. By contrast, lower concentrations of aspirin (10-8-10-7 M) or the COX-1 inhibitor SC-560 (3x10-8 M) did not affect these responses. The relaxation induced by acetylcholine was not affected by COX-1 and COX-2 inhibition (EC50 4.2x10-8M control, 7.4x10-8M, SC-560 and 6.3x10-8M nimesulide).
Conclusion:
Aspirin at high concentrations and the COX-2 selective inhibitor nimesulide potentiated the contractile response of gastroepiploic artery to adrenergic stimulation by inhibiting COX-2-derived PGI2. Aspirin at low concentrations and the COX-1 selective inhibitor SC-560 did not modify the contractile responses possibly due to minor importance of vasoconstrictor prostaglandins (TXA2) as active components of the response of gastroepiploic artery to adrenergic stimulation.
This work was supported by Conselleria de Educacion, Generalitat Valenciana
To cite this abstract, please use the following information:
Acta Physiologica 2009; Volume 195, Supplement 667 :P141