Facilitatory presynaptic angiotensin receptors on the sympathetic nerves of the human saphenous vein and pulmonary artery. Potential involvement in ?-adrenoceptor-mediated facilitation of noradrenaline release
- 1 September 1988
- journal article
- research article
- Published by Springer Nature in Naunyn-Schmiedebergs Archiv für experimentelle Pathologie und Pharmakologie
- Vol. 338 (3) , 228-233
- https://doi.org/10.1007/bf00173392
Abstract
Spirally cut strips of human saphenous vein and pulmonary artery preincubated with 3H-noradrenaline were superfused in the presence of corticosterone and desipramine or cocaine. In the saphenous vein angiotensin I, angiotensin II and angiotensin III concentration-dependently increased the electrically (2 Hz) evoked tritium overflow (relative order of potency: angiotensin II > angiotensin I > angiotensin III). The angiotensin receptor antagonist saralasin displaced the concentration-response curve of angiotensin II to the right, and also blocked the facilitatory effect of angiotensin III. Captopril, an inhibitor of angiotensin converting enzyme, did not modify the concentration-response curve of angiotensin I and did not significantly diminish the release-increasing effect of the nonselective β-adrenoceptor agonist isoprenaline, whereas saralasin attenuated the facilitatory effect of the β2-adrenoceptor agonist procaterol. In the pulmonary artery the angiotensin receptor agonist Val5-angiotensin II-Asp1-β-amide also increased the electrically evoked tritium overflow in a concentration-dependent manner. It is concluded that the sympathetic nerve fibres of the human saphenous vein (and probably of the human pulmonary artery as well) are endowed with facilitatory presynaptic angiotensin receptors. Angiotensin I exerted its facilitatory effect in the saphenous vein probably via direct stimulation of angiotensin receptors but not by conversion to angiotensin II. Furthermore, the β2-adrenoceptor-induced facilitation of noradrenaline release may in part be mediated by local stimulation of angiotensin II synthesis, which may occur by increased formation or activation of renin and/or increased availability of angiotensinogen.Keywords
This publication has 0 references indexed in Scilit: