Stress-induced decrease of uterine blood flow in sheep is mediated by alpha 1-adrenergic receptors.

Area of Science:

• Reproductive Physiology
• Neuroendocrinology
• Fetal Medicine

Background:

• Prenatal maternal stress impacts fetal development through mechanisms like reduced uterine blood flow (UBF).
• The specific adrenergic receptors mediating stress-induced UBF reduction remain largely unidentified.
• Alpha 1-adrenergic receptors are implicated in peripheral vasoconstriction and are present in uterine vasculature.

Purpose of the Study:

• To investigate the role of alpha 1-adrenergic receptors in mediating prenatal maternal stress-induced UBF decrease in sheep.
• To determine if blocking alpha 1-adrenergic receptors can prevent the reduction in UBF caused by maternal stress.

Main Methods:

• Chronic instrumentation of pregnant ewes (125±1 days of gestation).
• Acute isolation stress exposure (1 hour) at 130±1 days of gestation.
• Measurement of UBF, blood pressure, heart rate, and stress hormones before and during stress.
• Repetition of experiments after alpha 1-adrenergic receptor blockade with urapidil.

Main Results:

• Isolation stress increased norepinephrine, cortisol, blood pressure, and heart rate in ewes.
• Stress-induced decrease in UBF was observed in the absence of blockade.
• Alpha 1-adrenergic receptor blockade prevented the stress-induced reduction in UBF.

Conclusions:

• Alpha 1-adrenergic receptors mediate the decrease in uterine blood flow caused by prenatal maternal stress in sheep.
• Selective alpha 1-receptor blockade may be a strategy to prevent maternal-fetal stress transfer and protect fetal health.