Predominant role for nitric oxide in the relaxation induced by acetylcholine in human uterine artery

Abstract

The effect of acetylcholine on the isolated human uterine artery rings was investigated. Acetylcholine (10(-10) M to 6 x 10(-5) M) induced concentration- and endothelium-dependent relaxation (pD2 = 7.4 +/- 0.02, maximal response was 77.5 +/- 6.3% of relaxation induced by papaverine at 3 x 10(-4) M) of the pre-contracted arterial segments. Indomethacin (10(-5) M), diethylcarbamazine (10(-4) M) and tetra-ethylammonium (3 x 10(-4) M) had no effects on acetylcholine-evoked relaxation. Methylene blue (10(-5) M) and NG-monomethyl-L-arginine (L-NMMA) (3 x 10(-6) to 3 x 10(-5) M) antagonized relaxation induced by acetylcholine. The inhibition of endothelium-dependent relaxation by L-NMMA (10(-5) M) was reversed by L-arginine (10(-5) M) but not by D-arginine (10(-4) M). It is concluded that in uterine artery acetylcholine induces endothelium-dependent relaxation of isolated uterine artery is probably mediated via endothelial nitric oxide formation.

The role of nitric oxide in the process of implantation in rats

“…These substances have been reported to induce or modulate endogenous NO (Moneada et al, 1991;Jovanovic et al, 1994), an effector molecule that is well known for its vasoregulatory role (Molnar et al, 1994). It has been proposed that the effect of oestrogen on the uterus involves NO (Van Bruen et al, 1992).…”

“…Therefore, Dong et al (1996) proposed a possible role of NO in the adaptive vasodilatory changes in maternal circulation and the preservation of uterine quiescence for maintenance of pregnancy and initiation of labour. However, the relative contribution of NO varies depending on the species (Sladek et al, 1997 (Moneada et al, 1991;Jovanovic et al, 1994;Shifren et al, 1996). Oestrogen also stimulates uterine generation of NO by inducing available arginine (Van Bruen et al, 1992).…”

Endothelium‐dependent relaxation to acetylcholine in bovine oviductal arteries: mediation by nitric oxide and changes in apamin‐sensitive K+ conductance

“…Taken together, these findings provide evidence that the L-arginine-NO pathway is constitutively expressed in this tissue and seems to contribute to endotheliumdependent ACh relaxation through a mechanism involving guanylate cyclase activation and accumulation of cyclic GMP in smooth muscle. NO-dependent mechanisms mediating, in variable degree, ACh responses have been widely reported in several vascular preparations, including human uterine artery (Jovanovic et al, 1994b), rat mesenteric arteries (Hwa et al, 1994), guinea-pig carotid artery (Suzuki et al, 1992), rabbit (Mugge et al, 1991) and cat (Alonso et al, 1993) femoral arteries, human pulmonary arteries (Crawley et al, 1990) and gastric submucosal arterioles (Chen et al, 1993). We have shown that treatment of endothelium-intact vascular rings with L-NOARG enhanced the vasoconstrictor effect of NA, although it did not modify the resting vascular tone in most preparations.…”

Endothelial Denudation of Isolated Human Internal Mammary Artery Segments

“…Surface abrasion method: This traditional approach involves mechanical removal of the endothelium by gentle rubbing of the intimal surface with stainless-steel wire as described previously by Wackenfors [10] and Aleksandar [11].…”

“…Mechanical endothelial denudation has been undertaken in both animal and human isolated vessel via (1) the gentle rubbing of the luminal surface of the vessel with wooden stick [8], syringe needle [9], stainless steel wire [10,11], forcept [12], blunt seeker [13] and balloon…”