Oxytocin is a nine-amino acid peptide, the receptors of which can be found in various organs, including breast, kidney, or uterus. Hypothalamus is its primary source, but its synthesis occurs in various sites (Kilpatrick & Garrison, 2017). Oxytocin’s main functions are the stimulation of contractions, promotion of sexual arousal, and support of maternal-infant bonding. During the stimulation phase of parturition, oxytocin is released from the pituitary.
The oxytocin receptor is a type of protein, the activity of which is mediated by G-type proteins. During the stimulation phase (2), the level of these receptors increases considerably. They are usually concentrated in the myometrial cells and determine uterine activity in labor (Cunningham et al., 2018). The higher oxytocin receptors’ concentration in the body, the more evident the increase in uterine sensitivity is observed.