Lecture 2 -Neuroendocrinology II

Question 1

What is POMC?

Answer 1

Poopiomelanocortin is the pre-pro protein of ACTH and opiod peptides

Question 2

Where are the adrenal glands located?

Answer 2

Atom the kidney and are based in fatty tissue

Question 3

Which germ layer did the adrenal cortex stem from?

Answer 3

Mesoderm

Question 4

Which germ layer did the adrenal medulla stem from?

Answer 4

the neuroderm

Question 5

What is aldosterone important for?

Answer 5

Iron metabolism and facilitates na reabsorption

Question 6

Outline the HPA axis

Answer 6

Hypothalamus –> (CRH)–>Adenohypophysis –>(ACTH)–> Adrenal Medulla –> (Corticosterone and Cortisol) –> Blood
There is also nerve innervation to the medulla coming from the sympathetic nervous system –> stress hormone production

Question 7

How can the stress response be measured?

Answer 7

By measuring blood concentrations of ACTH and corticosterone

Question 8

What is the stress response dependent upon?

Answer 8

Quality of the stressor
Physiological Adaptations
Pathophysiological response

Question 9

What are the key behavioural adaptations peripartum?

Answer 9

Maternal behaviour
Child attachment and bonding
Altered emotionality i.e. maternal aggression, increased calmness and reduced anxiety

Question 10

What are the neuroendocrine adaptions peripartum?

Answer 10

Oestrogen/progesterone fluctuations
reduced resonsiveness of the HPA axis to stress
Increased activity of the oxytocin/prolactin system

Question 11

What are the mechanisms involved in maternal stress?

Answer 11

1. Perception of the stressor - reduced fos expression in limbic brain regions
2. Reduction in excitatory inputs to the PVN
3. Inhibitory action of the relevant neuropeptides
4. Reduction of the CRh system activity

Question 12

What are the two main functions of maternal stress?

Answer 12

to protect the baby against excessive levels of glucocorticoids
to balance the massive fluctuations in sexual steroids peripartum therefore being essential for maternal mental health

Question 13

What can severe stress during pregnancy cause?

Answer 13

Prevent adaptations to the CRH system thus creating post-partum depression

Question 14

What are the groups of post-partum disorders?

Answer 14

Maternity Blues - common
The pure post-partum depression - no history of depression
Women with a preivous history of major/minor depression - post-partum episode =most sever experienced
Post-partum psychosis - agitation, pressured speech, hallucinations, delusions, confusions and sever sleep disturbances

Question 15

What are the symptoms of non-psychotic post-partum depression?

Answer 15

Irritable, unhappy, anxious agitated, poor sleep and poor appetite

Question 16

What is CRF?

Answer 16

A neuropeptide in the brain which is synthesised in the PVN, where it’s synthesis is increased after acute stress

Question 17

What are the criteria for NPs in the brain?

Answer 17

Synthesis
ReleaSE
Receptors
Receptor mediated action
Behavioural relevane
Pyshiological relevance

Question 18

What are the pathophysiological adaptations of the CRF system in anxiety and depression?

Answer 18

Increased cortisol concentration in saliva
Increased cortisol
Lower plasma cortisol
Increased CRF in CSF

Question 19

What does CRF do?

Answer 19

Promotes passive stress coping
Reduces food intake
increases anxiety
increases arousal
stimulates sympathoadrrenal output
induces sleep disturbances
alters immune functions
inhibits sexual behaviour and reproductive functions

Question 20

Describe an animal model for depression/anxiety

Answer 20

Use HAB rats

Test on an elevated plus maze

Question 21

What happens when you trap mice on the outside arms of the elevated plus maze?

Answer 21

An increase in ACTH

Question 22

What single nucletotide polymorphism occurs in HAB rats?

Answer 22

In the vasopression gene causing increased vasopressin productionW

Question 23

What does the Dexamethasone-suppression/CRH challenge show in humans?

Answer 23

Pathological HPA axis hyperactivity
Involvement of endogenous AVp in depressed patients
Indicates pathological hyperactivity of AVP/CRH

Question 24

What diseases can chronic stress help cause?

Answer 24

Fibromyalgia
Chronic pain
Cancer
Bipolar disorder
PtS
Anxiety
Depression
IBD 
Rheumatoid arthritis
Burn out syndrome
asthma

Question 25

Outline a new model for showing stress in animals

Answer 25

the Chronic subordinate colony housing, helps mimic human stress by creating social stress in rodents. They do this by having two male mice in a cage, the macho mouse is 5g heavier therefore always wins. The macho mousse is changed on days 8, 15 and 19 to create constant social defeat.

Question 26

What are the consequences of chronic social defeat in rodents?

Answer 26

Reduced body weight gain
Reduced thymus weight
Increased adrenal weight
Adrenal hypertrophy yet adrenal insufficiency
HPA axis malfunction
inflammation
cellular immune functions
long lasting anxiety increase
impaired social behaviour
reduced neurogenesis

Question 27

How can early life stress affect adult stress?

Answer 27

It has an additive effect, so those that have early life stress are more likely to develop chronic social stress in adulthood, this can be pre or post-natal

Question 28

What type of vasopressin do all mammals have?

Answer 28

Arginine Vasopressin (AVP)

Question 29

What type of ‘vasopressin’ do all other vertebrates have?

Answer 29

Arginine Vasotocin (AVT)

Question 30

What type of ‘Oxytocin’ do different animals have?

Answer 30

Mammals - Oxytocin
fish, amphibians, reptiles, birds and marsupials - Mosotocin
Some fish - Isotocin

Question 31

What are the stimuli for central release of oxytocin?

Answer 31

Birth
Suckling
Stress
Sex

Question 32

What are the stimuli for peripheral release of oxytocin?

Answer 32

Birth
Sucking
Stress
Sex

Question 33

What are the stimuli for central release of vasopressin?

Answer 33

Stress

Maternal Behaviour

Question 34

What are the stimuli for peripheral release of vasopressin?

Answer 34

Osmotic challenge

Blood loss