Different effects of protamine on canine coronary microvessel and conductance arteries : evidence of hyperpolarizing factor release

BACKGROUND: Protamine administration may lead to systemic hypotension, perhaps because of vasodilatation produced by endothelial nitric oxide. This study compared release of vasoactive substances from canine coronary microvessels with that from paired conductance arteries.

METHODS: Microvessels were mounted in a videoscopic no-flow system, and circumflex arteries were studied in organ chambers; both were induced to contract by endothelin-1.

RESULTS: Protamine (10 to 160 micrograms/mL) produced concentration-dependent relaxation in both microvessel and conductance arteries (46% +/- 14% maximal relaxations in microvessel and 82% +/- 15% in conductance arteries, n = 10 each). Removal of the endothelium abolished this relaxation (P < .05, n = 6). Indomethacin (10(-5) mol/L) did not alter the relaxation in either group (51% +/- 10% in microvessel and 103% +/- 7% in conductance arteries, n = 6 each). NG-monomethyl-L-arginine (L-NMMA, 10(-4) mol/L) attenuated relaxation in conductance arteries (38% +/- 12%, P = .04, n = 6) but had no effect on microvessel arteries (58% +/- 10%, n = 6). Tetraethylammonium chloride (10(-3) mol/L), an inhibitor of voltage-dependent potassium channels, had no effect on conductance arteries (103% +/- 9%, n = 6) but abolished relaxation in microvessels (-25% +/- 11%, P = .03, n = 6).

CONCLUSIONS: Protamine sulfate causes endothelium-dependent relaxation in microvessel and conductance arteries in the heart by different mechanisms--that is, by nitric oxide release in conductance arteries and by endothelium-derived hyperpolarizing factor (EDHF) release in microvessels. This is the first description of the release of EDHF in response to protamine administration.

Medienart:

Artikel

Erscheinungsjahr:

1999

Erschienen:

1999

Enthalten in:

Zur Gesamtaufnahme - volume:126

Enthalten in:

Surgery - 126(1999), 5 vom: 15. Nov., Seite 835-41

Sprache:

Englisch

Beteiligte Personen:

Cable, D G [VerfasserIn]
Sorajja, P [VerfasserIn]
Oeltjen, M R [VerfasserIn]
Schaff, H V [VerfasserIn]

Themen:

31C4KY9ESH
Biological Factors
DCR9Z582X0
Endothelium-dependent hyperpolarization factor
Epoprostenol
Heparin Antagonists
Journal Article
Nitric Oxide
Protamines
Research Support, Non-U.S. Gov't

Anmerkungen:

Date Completed 30.11.1999

Date Revised 07.12.2017

published: Print

Citation Status MEDLINE

Förderinstitution / Projekttitel:

PPN (Katalog-ID):

NLM104981660