Inflammation changes the expression of neuropeptide Y receptors in the pig myometrium and their role in the uterine contractility

Abstract

In the experiment the influence of inflammation on neuropeptide Y (NPY) receptor subtype 1 (Y1Rs) and 2 (Y2Rs) expression pattern in the gilt myometrium and NPY effect alone or with Y1Rs and Y2Rs antagonists on contractility of an inflamed uterus were recognized. On Day 3 of the estrous cycle, either E.coli suspension (E.coli group) or saline (SAL group) were administered into uterine horns. In the control gilts (CON group), only laparotomy was carried out. Eight days later, E.coli treatment evoked severe acute endometritis, significantly reduced Y1Rs mRNA and protein expression and increased Y2Rs protein expression in myometrium in relation to the CON and SAL groups. Compared to period before NPY application, NPY (10 −7 M) significantly reduced amplitude in myometrium and endometrium/myometrium and frequency in myometrium of the CON and SAL groups and amplitude in endometrium/myometrium and frequency in strips of the E.coli group. In this group, after using NPY (10 −7 M), the amplitude rose significantly in both kinds of strips, while frequency fell in endometrium/myometrium in relation to the SAL group. In the CON and SAL groups, NPY (10 −7 M) with Y1Rs antagonist significantly increased the amplitude in endometrium/ myometrium, while with Y2Rs antagonist caused a rise in myometrium. In the E.coli group after using Y1Rs or Y2Rs antagonist and NPY (10 −7 M) amplitude did not significantly change in endometrium/myometrium, and this parameter was significantly lower after using the NPY and Y1Rs antagonist than in other groups. Y1Rs antagonist and NPY (10 −8 , 10 −7 M) significantly increased frequency in endometrium/myometrium of the CON and SAL groups. In the E.coli group, Y1Rs or Y2Rs antagonists and NPY (10 −7 M) significantly increased frequency in myometrium and it was significantly higher than in the CON group. Inflammation changes Y1Rs and Y2Rs expression in myometrium of the inflamed pig uterus and NPY reduces this organ contractility by Y1Rs and Y2Rs.

Role of beta-adrenergic receptor subtypes in pig uterus contractility with inflammation

“…In this regard, it is very important to know the mechanisms, including neurogenic, regulating contractility of the pathologically-changed uterus. Several studies have presented the role of (acetylcholine) ACh 42 , neuropeptide Y 43 , somatostatin 44 and vasoactive intestinal peptide 45 with the participation of their receptors in the neuronal regulation of inflamed uterus contractility. The effect of NA on the contractile activity of inflamed uterus 32 , 46 as well as ARs expression in the pathologically-altered uterus 33 have also been studied.…”

Regulatory Influence of Galanin and GALR1/GALR2 Receptors on Inflamed Uterus Contractility in Pigs

“…Regarding the clinical aspect of findings revealed in the present study, it can be hypothesized that by lowering the amplitude of the inflamed pig uterus, GAL favors the accumulation of inflammatory exudate inside the uterus, such as PGE 2 , NA, ACh, NPY, and VIP [11,13,16,17,19]. In turn, GAL increased myometrial frequency in the gilts of the E. coli group, similarly to PGF 2α , PGI 2 , LTC 4 , and ACh [11,12,14,16].…”

“…This is due to the high importance of disturbances of this uterine activity for the origin and control of inflammation and consequences of this process [2,6]. It is known that the effect of PGs, LTs, NA, ACh, NPY, SOM, and VIP on contractile amplitude and frequency in pigs partly differs between myometrium and endometrium/myometrium stripes [11][12][13][14][16][17][18][19]. Therefore, the role of GAL and its receptors was investigated using two kinds of uterine stripes.…”

“…The pieces of uterine horns were cut in a cryostat (Reichert-Jung, Nußloch, Germany), and the obtained sections (10 µm thickness) were stained using the single-immunofluorescent method, as previously described [17]. Briefly, after drying (at 21 • C, for 30 min) and rinsing (0.1M PBS, pH = 7.4, three times, each for 15 min), uterine sections were incubated (at 21 • C, for 1 h) with a buffered blocking mixture with the following composition: 0.1 M PBS, 10% normal goat serum (MP Biomedicals, Solon, OH, USA), 0.1% bovine serum albumin (Sigma-Aldrich, St. Louis, MO, USA), 0.05% Thimerosal (Sigma-Aldrich, St. Louis, MO, USA), 1% Triton X-100 (Sigma-Aldrich, St. Louis, MO, USA), and 0.01% sodium azide.…”

“…In postpartum cows, oxytocin positively influences the inflamed uterus contractility, while PGF 2α induces an initial decrease in contraction, followed by an increase [15]. In reference to the regulation of uterine contractility with inflammation by neurotransmitters, the role of noradrenaline (NA), acetylcholine 2 of 16 (ACh), neuropeptide Y (NPY), somatostatin (SOM), and vasoactive intestinal peptide (VIP) [11,13,[16][17][18][19] and the expression of adrenergic and muscarinic receptors [20,21] in diseased porcine organs were reported. Moreover, in the pregnant rats with uterine inflammation, tumor necrosis factor-α mediates the increase of uterine relaxation induced by β 2 -adrenergic receptor agonists [22].…”