[The effects of heparin on intrauterine arteries of the human non-pregnant uterus: I. The action of clinically administered heparin].
OBJECTIVE
Our purpose was to study the action of commercial unfractionated heparin on small human myometrial arteries, in vitro.


METHODS
Pieces of myometrial arteries, about 1 mm. in external diameter, were obtained from premenopausal women undergoing hysterectomy. Responses of arteries to K(+)-depolarisation and vassopressin were recorded under isometric condition. Free calcium concentration was determined with ion-selective electrode.


RESULTS
Commercial heparin did not change basal tension of myometrial strips. Depolarised K+ strips were relaxed by heparin in concentration-dependent manner. Inhibition of NO synthase or endothelium denudation do not significantly change the reaction to heparin of strips precontracted with K(+)-depolarisation. There was a time-dependent reduction of the arterial response to vasopressin after incubation with heparin. The calcium ion chelation caused by heparin at concentrations up to 220 IU/mL did not account for the relaxation of uterine arteries.


CONCLUSIONS
Our results suggest that clinically observed hypotensive effect of the commercial heparin is caused by its direct action on arterial smooth muscle.
Litorowicz
A
A
Zakładu Patofizjologii Ciazy Instytutu Połoznictwa i Chorób Kobiecych AM w Białymstoku.
Laudańska
H
H
Kostrzewska
A
A
D005260:Female; D006493:Heparin / Q000493:pharmacokinetics*; D006801:Humans; D007044:Hysterectomy; D009215:Myometrium / Q000378:metabolism; D014599:Uterus / Q000378:metabolism*
D006493:Heparin