W4 pre: Vasopressin/oxytocin-type neuropeptide signalling

Where are neuropeptides vasopressin and oxytocin released from?

posterior pituitary gland

What is a vasopressive effect?

increase in blood pressure

What is a vasodilative effect?

decrease in blood pressure

Who isolated and named oxytocin and vasopressin?

Kamm et al

List 2 effects of oxytocin

• uterine contraction

• lactation

List 2 effects of vasopressin

• increase in blood pressure

• anti-diuretic

What is neurophysin?

a carrier protein made in the hypothalamus that transport oxytocin and vasopressin to be secreted from the posterior pituitary gland

What disease can mutations in the neurophysin-vasopressin precursor gene cause?

diabetes insipidus

How does a mutation in the neurophysin-vasopressin gene cause diabetes insipidus?

defective production of vasopressin due to a missense mutation results in failure to transport vasopressin by converting a highly conserved glycine to a valine residue

How many receptors does vasopressin bind to?

three

How many receptors does oxytocin bind to?

one

List 3 vasopressin receptors

• Vasopressin V1a receptor

• Vasopressin V1b receptor

• Vasopressin V2 receptor

List 4 sites that Vasopressin V1a receptors are expressed in

• vascular and smooth muscle

• hepatocytes

• uterus

• brain

List 2 sites that Vasopressin V1b receptors are expressed in

• anterior pituitary

• brain

What is the downstream effect of binding to Vasopressin V1 receptors?

coupling to phospholipase C

List 2 sites that Vasopressin V2 receptors are expressed in

• kidneys

• liver

What is the downstream effect of binding to Vasopressin V2 receptors?

stimulation of adenyly cyclase activity

List 3 sites that Oxytocin receptors are expressed in

• uterus

• mammary glands

• brain

What is the downstream effect of binding to Oxytocin receptors?

coupling to phospholipase C

State a behavioural role of vasopressin (2 points)

• stimulates behaviours associated with monogamy (parental, care, mate guarding, selective preference for their mate) in male prarie voles

• appears to be due to differences in the expression of the V1a vasopressin receptor in the brain