lecture 10 LOs Flashcards

1
Q

dopamine receptor subtypes amount and type

A

five subtypes, D1-5
all metabotropic
D1 and 5 are similar, D2-4 are similar

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2
Q

what does D1 dopamine receptor activation stimulate

A

adenylyl cyclase and cAMP synthesis

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3
Q

what does D2 domaine receptor activation do

A

reduces cAMP and inhibits adenylyl cyclase

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4
Q

what is the difference between where D1/D2 and D3/D4 receptors are found

A

D1/2 found in all brain regions that get DA innervation (but not necessarily both in all areas)
D3/4 receptors show more regional variations

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5
Q

what do D2 type receptors function as and what do their antagonists do

A

function as both autoreceptor and postsynaptic receptor
D2 antagonists increase DA release (by blocking the autoreceptor) but also reduce postsynaptic DA signalling

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6
Q

do D1 or D2 receptors have higher affinity for DA

A

D2

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7
Q

what does it mean that some DA receptors are _____ on glutamate/GABA terminals that _____

A

heteroreceptors
modulate fast transmission presynaptically

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8
Q

what does the DA agonist apomorphine do

A

stimulate D1 and D2 receptors
casues behavioural activation similar to that seen w cocaine or amphetamine
DA receptor agonists are used for treatment of parkinsons

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9
Q

what does DA antagonist flupenthixol do

A

blocks both D1-D2 receptors
reduces motivaton at higher doses produces catalepsy (lack of spontaneous movement) like all D1 or D2 antagonists

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10
Q

what does DA antagonist haloperidol do

A

highly selective for D2 vs D1 but will bind to the entire D2 like family similarily

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11
Q

what happens if D2 antagonist is given repeatedly over 12 days

A

rats develop behavioural supersensitivity
after chronic treatment the dose no longer is effective at blocking AMPH
then when the antagonist treatment is stopped the DA agonist has greater locomotor response

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12
Q

where are norepinephrine (NE) neuron cell bodies in the central nervous system

A

NE neuron cell bodies resude in the pons and medulla in the brain stem
locus coeruleus in the pons is a dene collection of NE neurons

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13
Q

where do NE anxons of the central nervous system extend to

A

nearly all of the forebrain as well as the cerebellum and the spinal cord

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14
Q

where is NE released from in the peripheral nervous system

A

sympathetic noradrenergic neurons at synapse like contacts
adrenal glands and travel in the bloodstream to target organs (cannot cross blood brain barrier)

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15
Q

NE receptor subtypes

A

alpha and beta
both metabotropic
distributed widely across cortical and subcortical sites

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16
Q

what do alpha1 receptors for NE operate w

A

phosphoinositide 2nd messenger system (post synaptic)

17
Q

what are the a1 NE receptor agonist and antagonist

A

agonist: phenylephrine
antagonist: prazosin

18
Q

what does the a2 NE receptor do

A

reduce cAMP synthesis (like a D2 receptor) and serves as presynaptic autoreceptor and postsynaptic receptor

19
Q

what is the a2 NE agonist and antagonist

A

agonist: clonidine
antagonists: yohimbine

20
Q

what do b1 and b2 NE receptors do

A

stimulare adenylyl cyclase and enhance synthesis of cAMP (like D2 receptors)

21
Q

what are the agonist and antagonist of b2 NE receptor

A

agonist: isoprotenerol (increase heart rate)
antagonist: propanolol (decrease heart rate)

22
Q

NE is key for maintaining arousal, waht happens to do this

A

Locus coerelus neurons fire more rapidly during waking vs sleep
almost completely silent in REM tho

23
Q

what NE projections promote wakefulness

A

to medial septal and medial preoptic areas

24
Q

what does a pharmacological increase in NE promote

A

anxiety like feelings

25
Q

what does yohimbine do regarding NE release and beh effects

A

increases NE release, induces anxious like beh

26
Q

what does NE regulate

A

congitive functions mediated by prefrontal cortex (attention and working mem)

27
Q

what does activation of pre frontal cortex a2 receptors do

A

increases working memory impairments
likely happens via activation of postsynaptic a2 receptors, rather than via reduced NE release

28
Q

NE facilitates ___ via activation of ___

A

PFC function
postsynaptic a2 receptors

29
Q

stress causes what to happen to PFC NE levels

A

excessive increase
impaired cog function

30
Q

steps of stress induced impairment in PFC function and a1-receptors

A

stimulate PFC a1 receptor impairs cognition
antagonizing PFC a1 receptor can increase stress induced impairments
NE has lower affinity for PFC a1 receptors vs a2 receptors
stress can induce larger than normal increases in NE levels which increases a1 receptor activation which leads to cog impairment

31
Q

how do strong emotional states affect memory consolidation

A

enhance it
may be mediated NE in part

32
Q

what does a beta adrenergic receptor antagonist do

A

disrupts enhancement of memory for emotional content (not neural content) but subjects still have an emotional response to the story

33
Q

what do stressful events do to NE

A

increase its release in the amygdala
this can enhance consolidation of memories
can be part of PTSD

34
Q

what can stress cause in the PFC

A

increase in NE levels which impair cognitive function