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

Abstract

Uterine inflammation is a very common and serious condition in domestic animals. To development and progression of this pathology often lead disturbances in myometrial contractility. Participation of β1-, β2- and β3-adrenergic receptors (ARs) in noradrenaline (NA)-influenced contractility of the pig inflamed uterus was studied. The gilts of SAL- and E.coli-treated groups were administered saline or E.coli suspension into the uterine horns, respectively. Laparotomy was only done in the CON group. Compared to the period before NA administration, this neurotransmitter reduced the tension, amplitude and frequency in uterine strips of the CON and SAL groups. In the E.coli group, NA decreased the amplitude and frequency, and these parameters were lower than in other groups. In the CON, SAL and E.coli groups, β1- and β3-ARs antagonists in more cases did not significantly change and partly eliminated NA inhibitory effect on amplitude and frequency, as compared to NA action alone. In turn, β2-ARs antagonist completely abolished NA relaxatory effect on these parameters in three groups. Summarizing, NA decreases the contractile amplitude and frequency of pig inflamed uterus via all β-ARs subtypes, however, β2-ARs have the greatest importance. Given this, pharmacological modulation of particular β-ARs subtypes can be used to increase inflamed uterus contractility.

Figure 1

Effect of noradrenaline (NA) on the tension (A, D), amplitude (B, E) and frequency (C, F) of contraction in myometrium (A–C) and endometrium/myometrium (D–F) strips of gilts from the CON (grey bars), SAL (hatched bars) and E. coli (black bars) groups. Data obtained from five experiments (gilts, in each group). Effects of particular doses of NA are presented as a percentage (mean ± SEM) in relation to the basal (pre-treatment period) tension, amplitude and frequency, accepted as 100% (horizontal lines). *P < 0.05, **P < 0.01, ***P < 0.001—indicate differences in the comparison to the basal value in each group; ^aP < 0.05—indicates a difference between the CON and E. coli groups for the same treatment; ^bP < 0.05, ^bbP < 0.01, ^bbbP < 0.001—indicate differences between the SAL and E. coli groups for the same treatment.

Figure 2

Effect of noradrenaline (NA) on the tension (A, D), amplitude (B, E) and frequency (C, F) of contraction in myometrium (A–C) and endometrium/myometrium (D–F) strips of gilts from the CON (grey bars), SAL (hatched bars) and E. coli (black bars) groups in the presence of β1-ARs antagonist. Data obtained from five experiments (gilts, in each group). Effects of β1-ARs antagonist and particular doses of NA are presented as a percentage (mean ± SEM) in relation to the basal (pre-treatment period) tension, amplitude and frequency, accepted as 100% (horizontal lines). *P < 0.05, **P < 0.01, ***P < 0.001—indicate differences in comparison to the basal value in each group; ^aP < 0.05—indicates a difference between the CON and E. coli groups for the same treatment; ^bP < 0.05—indicates a difference between the SAL and E. coli groups for the same treatment.

Figure 3

Effect of noradrenaline (NA) on the tension (A, D), amplitude (B, E) and frequency (C, F) of contraction in myometrium (A–C) and endometrium/myometrium (D–F) strips of gilts from the CON (grey bars), SAL (hatched bars) and E. coli (black bars) groups in the presence of β2-ARs antagonist. Data obtained from five experiments (gilts, in each group). Effects of β2-ARs antagonist and particular doses of NA are presented as a percentage (mean ± SEM) in relation to the basal (pre-treatment period) tension, amplitude and frequency, accepted as 100% (horizontal lines). ***P < 0.001—indicates a difference in the comparison to the basal value in each group; ^aP < 0.05—indicates a difference between the CON and E. coli groups for the same treatment; ^bP < 0.05—indicates a difference between the SAL and E. coli groups for the same treatment; ^cP < 0.05—indicates a difference between the CON and SAL groups for the same treatment.

Figure 4

Effect of noradrenaline (NA) on the tension (A, D), amplitude (B, E) and frequency (C, F) of contraction in myometrium (A-C) and endometrium/myometrium (D–F) strips of gilts from the CON (grey bars), SAL (hatched bars) and E. coli (black bars) groups in the presence of β3-ARs antagonist. Data obtained from five experiments (gilts, in each group). Effects of β3-ARs antagonist and particular doses of NA are presented as a percentage (mean ± SEM) in relation to the basal (pre-treatment period) tension, amplitude and frequency, accepted as 100% (horizontal lines). *P < 0.05, **P < 0.01, ***P < 0.001—indicate differences in the comparison to the basal value in each group; ^aaaP < 0.001—indicates a difference between the CON and E. coli groups for the same treatment; ^bP < 0.05, ^bbbP < 0.001—indicate differences between the SAL and E. coli groups for the same treatment; ^cP < 0.05—indicates a difference between the CON and SAL groups for the same treatment.

Figure 5

Diagram showing treatment of the uterine strips. Ach—acetylcholine; NA—noradrenaline; β1-ARs anta.—adrenergic β receptor subtype 1 antagonist; β2-ARs anta.—adrenergic β receptor subtype 2 antagonist; β3-ARs anta.—adrenergic β receptor subtype 3 antagonist. Concentrations of the used substances are given in moles.