L5 Stress-related disorders Flashcards
Acute physiological stress activates…
(i) the sympatho-adrenal medullary (SAM) system
(ii) the hypothalamic-pituitary adrenal (HPA) axis
CRH is produced by
PVN of hypothalamus
What happens when CRH binds its receptors?
stimulation of cAMP pathway, ACTH release
How does cortisol exert its effects?
by binding to glucocorticoid receptors
How is the HPA axis regulated?
- negative feedback
- diurnal rhythm
What are the consequences of stress?
Acute = adaptation
Chronic = maladaptation –> disorders
Behavioural models of anxiety
EPM and light/dark
Behavioural models of depression
social interaction and FST
Behavioural model of learning and memory impairment
RAWM
Two types of chronic psychosocial stress measured using animal models
- chronic unpredictable variable stress (decreased sucrose preference, increased immobility in FST)
- social defeat stress (increased immobility, decreased social interaction, decreased sucrose preference)
Model of single prolonged stress
PTSD - inescapable shock, predator stress, single prolonged stress, chronic restraint
Effect of PTSD on HPA output
reduced HPA output
Effect of major depression or chronic stress on HPA output
increased HPA output
Model of early-life stress-induced pain
Maternal separation
Effect of PTSD on HPA axis
HPA axis hypoactivation
- blunted response to CRH
- reduced ACTH output
- low circulating cortisol
- GR hypersensitivity
- altered negative feedback loop