RELAXANT EFFECTS OF ALPHA-HUMAN ATRIAL-NATRIURETIC-PEPTIDE ON VENOUS SMOOTH-MUSCLE

• Type: Article in International Scientific Journal
• Date: 1991

Authors

VILLANUEVA, MM (Author) Other; José Pedro Nunes (Author) FMUP; soares-da-silva, p (Author) FMUP

Journal

Title: Journal of Autonomic Pharmacology

Vol. 11

Pages: 139-145

ISSN: 0144-1795

Publisher: Blackwell

Indexing

ISI Web of Knowledge - 4 Citations

Scopus - 4 Citations

Other information

Authenticus ID: P-001-QPN

DOI: 10.1111/j.1474-8673.1991.tb00313.x

Abstract (EN): 1 The present study has examined the relaxant effects of alpha-human atrial natriuretic peptide (alpha-hANP) and sodium nitroprusside on dog saphenous vein ring preparations; responses were tested on a background of tone corresponding to 30% and 80% of maximal contraction. Also tested on the lower background of tone were the responses to carbachol, M&B 22,948, forskolin and 3-isobutyl-1-methylxanthine (IBMX). The vascular responses to alpha-hANP and carbachol were also examined in dog splenic artery ring preparations. 2 On a background of tone corresponding to 30% of maximal contraction, both alpha-hANP and sodium nitroprusside were found to relax venous ring preparations with IC50 values of 6 x 10(-8) and 2 x 10(-7) M, respectively. When the background of tone was raised to 80% of maximal contraction, the relaxant effect of sodium nitroprusside was significantly reduced and that of alpha-hANP became almost completely abolished; the IC50 value for sodium nitroprusside in these experimental conditions was 2 x 10(-6) M. 3 The cGMP phosphodiesterase inhibitor M&B 22,948 was found to produce a concentration-dependent relaxation, with an IC50 value of 2 x 10(-6) M in saphenous vein rings with a background of tone corresponding to 30% of maximal contraction. By contrast, saphenous vein rings were found to be insensitive to carbachol. Forskolin and IBMX were also found to produce concentration-dependent relaxing responses of venous preparations, with IC50 values of 2 x 10(-7) and 7 x 10(-7) M, respectively. 4 Dog splenic artery rings were found to relax to alpha-hANP and to respond effectively to the endothelium-dependent relaxation elicited by carbachol. 5 The results presented demonstrate that the relaxant responses to alpha-hANP and to sodium nitroprusside in dog saphenous vein rings are dependent on the background of tone in which the responses were tested. Furthermore, the dog saphenous vein preparation is fully capable of relaxing in response to increased levels of cGMP or cAMP generated by M&B 22,948 and by Forskolin and IBMX, respectively.

Language: English

Type (Professor's evaluation): Scientific

No. of pages: 7