Oxytocin

 

Function

 

 

 

Regulation of Expression

 

Oxytocin is released in response to cervical stretch during labor. Oxytocin release causes uterine contractions, which pushes against the cervix, which in turn causes more oxytocin release. This positive feedback loop (the ferguson reflex) happens quickly because of oxytocin's cell surface signaling. Uterine contraction also causes prostaglandin release, another positive feedback loop.

A difficult delivery is sometimes facilitated by oxytocin administration.

The sound of a baby's cry, and the suckling reflex, acts on higher brain centres to induce oxcytocin release and remove inhibition on prolactin release, causing both smooth muscle contraction and milk secretion.

 

 

Consequences of Overexpression

Overexpression of PRL (hyperprolactinemia) can lead to galactorrhea

 

Consequences of Underexpression

 

 

Signalling Pathways

It is also released as a neurotransmitter thought to reach down to the amygdala, where it may facilitate bonding and trust.

It cannot cross the BBB, and systemic oxytocin is only thought to work peripherally.

Oxytocin is a nonapeptide arranged in a ring. (get picture) it shares all but two amino acids with ADH, or vasopressin.

It is normally produced by magnocellular neurons which release their contents as neurotransmitter and a hormone from the

 

 

Structure