Oxytocin and vasopressin Flashcards
1
Q
Describe vasopressin
A
- Also known as arginine vasopressin
(AVP), antidiuretic hormone (ADH), or
argipressin - Functions principally as a
vasoconstrictor and antidiuretic - Modulates aquaporin (water channels)
in kidney nephron increasing water
resorption - Important regulator of water, glucose,
and salt homeostasis
1
Q
Describe oxytocin
A
- One of only two hormones
released from the posterior
pituitary - Described in 1906 as a compound
able to elicit uterine contraction - Identified and synthesized in 1953
- Classic hormone roles in labour
and lactation
2
Q
Describe expression and function of OXT/AVP
A
- Cleavage of the preproOXT/AVP polypeptides give rise to OXT and AVP and an additional carrier protein (~90 amino acids)
- preproOXT yields Neurophysin I
- preproAVP yields Neurophysin II
3
Q
Describe oxytocinergic neurons
A
- Oxytocinergic neurons project
from the paraventricular
nucleus of the hypothalamus
to the forebrain and hindbrain - Notable innervation of the
amygdala, NAc & VTA,
hippocampus
4
Q
Describe oxytocin systems
A
- Oxytocinergic neurons project from the paraventricular nucleus of the
hypothalamus to the forebrain and hindbrain
5
Q
Describe microtine rodents
A
Prairie voles (Microtus ochrogaster) live in colonies and form life-long monogamous bonds.
Share huddles, grooming, nesting, and pup-
rearing responsibilities.
6
Q
Describe microtine rodent relevance to oxytocin
A
- Microtine voles are commonly used in a lab setting to examine social behaviours, bonding,
and investigating the underlying neurochemistry of social behaviour. - Social behaviours can be measured using simple tests such as partner preference – measuring time spent interacting with a bonded partner vs a strange
7
Q
Describe oxytocin receptor audio graph
A
OXTR binding
capacity correlates
with social behaviour
(measured by partner
preference tests)
8
Q
Describe its link to early social interactions
A
- Human infants with high parent-infant synchrony (i.e. enhanced capacity to respond to
infant’s socio-affective signals) have increased OXT levels in saliva compared with low parent-
infant synchrony - Effects seem to be cross-generational
- Human parents with high parent-infant synchrony also show increased salivary OXT
9
Q
Describe genetic manipulation of OXT
A
- Social behaviours can be restored in OXT/R KO models by intracerebroventricular
injection of OXT before but not after initial social exposure - Suggests a role of OXT in encoding but not recall of social information
- Possible role in enhancing saliency of social information
10
Q
Describe link between OXT and autism
A
- Persistent deficits in social communication and interaction
- Restricted and repetitive patterns of behaviour
11
Q
Describe oxytocin pharmacology
A
- Oxytocin IV is used clinically to induce labour
- Induces uterine contractions
- IV administration has a half-life of ~ 3 minutes
- Oxytocin has been explored to induce or facilitate lactation
- Intranasal oxytocin has been used to investigate behavioural effects of
OXT - Intranasal administration can bypass the BBB and prolongs the bioavailability
of OXT - Intranasal OXT is psychoactive and effects last 2-4 hours
12
Q
Describe effects in healthy controls
A
- IN-OXT increases social cognition in healthy controls
- IN-OXT decreases emotional processing
- IN-OXT administration increases disclosure of emotional events when recalling autobiographical
stories - Using trust games such as risky-investment scenarios IN-OXT increased subjects ratings of
‘trustworthiness’ and generally gave more ‘money’ to trustworthy recipients
13
Q
Describe link between social salience and oxytocin
A
- Many facets of both pro- and anti-social behaviour are
enhanced by OXT administration - IN-OXT may reinforce or exacerbate in-group/out-group differences
14
Q
Describe stop distance paradigm
A
- Subjects (male volunteers) are placed into an
encounter with an attractive female experimenter - Distance was varied between the subject and
experimenter until the subject reaches a
comfortable distance (ideal distance) - Administration of intranasal OXT (but not placebo)
had a specific effect on subjects in a relationship - Suggest OXT may reinforce fidelity
