Week 3 - Anxiety Flashcards
What are the 2 main hormonal reactions to fear?
Cortisol
Noradrenaline
What part of the brain activates when aroused by fear?
The amygdala
Amygdala alerts other brain structures including the hypothalamus and the locus coruleus
Information is then sent from the thalamus to the cortex and basal ganglia for processing
What is the main neurotransmitter for GAD?
Noradrenaline - overacting in central and peripheral nervous system
Serotonin in GAD
Increased activity due to a lack of serotonin in:
Basal Ganglia
-inability to adequately process information from the environment
Cerebral Cortex (PFC)
Limbic cortex/Amygdala
5HTa1 receptors!
Neurotransmitters for OCD
Noradrenaline
Seratonin
Dopamine
Which 2 brain areas causes OCD?
Lack of communication between
Frontal (cingulate), striatal and thalamic structures
Noradrenaline in OCD
don’t have sympathetic outflow
Serotonin in OCD
Increased activity due to LACK of serotonin in:
Basal ganglia/thalamus
Cerebral Cortex (PFC)
Hippocampus (memory)
Limbic cortex/Amygdala
Dopamine in OCD
Increased dopamine function in basal ganglia(nigrostriatal) produces repetition of habits
PTSD amygdala and hippocampus
Amygdala dominates information from the hippocampus - leads to exacerbation of negative emotion linked to the memory or event
What does the hypothalamus do?
Regulates autonomic nervous system (peripheral)
3 main brain structures in PTSD
Hippocampus
Amygdala
Hypothalamus
Pituiatry gland activates: cortisol
What activates the hippocampus?
cortisol
more cortisol - the hippocampus shrinks/cells kill neural pathway of hippocampus to hypothalamus
Hippo is less efficient at inhibiting ACTH release
amydala takes over
Common neural circuits of anxiety
All noradrenaline systems are overactive
Select serotonin neurons are underactive
OCD also has increased dopamine in BG area
How do barbituates work?
gaba a receptor agonists - enhance IPSP of chloride receptor
How do benzo’s work?
gaba agonists
have their own binding site on gaba receptors - Bz1 and Bz2
Allows for chloride to get in by binding to receptor site and opening the channel - allows channel to stay open for longer - more IPSP
Pro’s on benzo’s
Reduce anxiety and aggression
can produce sedation for insomnia
effective immediately is taken orally
2nd generation anxiety meds
decrease noradrenaline
increase seratonin
What drugs decrease noradrenaline for anxiety and how do they work?
B-adrenoreceptor antagonists (beta blocker) - stop the production of noradrenaline with produces sympathetic overload
What drugs increase seratonin for anxiety and how do they work?
5HT1A receptor - agonists - increase IPSP - acts like seratonin
SSRI’s - stop the re-uptake of seratonin after post-synaptic potentialW
What protein is involved in serotonin
Gi - inhibitory G protein
SSRi’s
Kepp seratoinin in the synapse - block re-upatke
With next action potential - more serotonin stays in the synapse
What is the latency to become effective?
5 Ht1A receptors are also pre-synaptic and are more sensitive
When serotonin binds pre-synaptically, serotonin release is stopped
Cells need to de-sensitise and remove themselves before drugs can be effective (2-3 weeks) - usually why people don’t see affect for this time
Need to de-sensitse
