Neurotransmitters

Question 1

the major neurotransmitters

Answer 1

ANother Silly Duck Goes Gambling

acetylcholine
norepinephrine/noradrenaline
serotonin
dopamine
GABA
glutamate

Question 2

acetylcholine

Answer 2

pontomesencephalic regions and nuclear groups of BF

indirect excitation of thalami-cortical projection

attention, memory, regulation of thalamic output

2 receptors: muscarinic (mediate the main cognitive effects attributed to cholinergic pathways with effects on attention, learning, STM) and nicotinic (trigger rapid neural and neuromuscular transmission within sympathetic and parasympathetic NS and at neuromuscular junction)

drugs with strong anticholinergic properties (antihistamines, first generation antipsychotics, tricyclic antidepressants) may exert negative effects on cognitive performance in those areas, esp to elderly or ppl with reduced cognitive reserve

disruption in cholinergic NTmission due to damage of BG widespread effects on cortical and limbic projections, produce neurobx syndromes like amnesia, dysexecutive, frontally mediated confabulation

antihistamines may produce sedation and cognitive inefficiency thru cholinergic and serotonergic systems

Question 3

norepinephrine/noradrenaline

Answer 3

locus coeruleus and lateral tegmental area

excitation/facilitation

attentional shifting, arousal, mood, sleep-wake cycle, modulating pain

“stress hormone”

role in depression, bipolar, anxiety/OCD

cholinergic and serotonergic activation can inhibit NE neurotransmission

adhd meds increase NE and dopamine; atomoxetine (Strattera) is a specific NE rey-take inhibitor so only affects NE

meds that treat hypertension, cardiac arrhythmia, glaucoma, migraines broad effect on B-adrenergic function

Question 4

serotonin

Answer 4

rostral and dorsal raphe

post-synaptic inhibition

mood, arousal, pain, respiration, temperature, motor control

bc of the projection, it plays a role in anxiety, depression, OCD, aggresive bus, EDs

drugs affecting serotonin metabolism usually prescribed for depression, GAD, social phobia - SSRI (fluoxetine, sertraline), SNRI (venlafaxine) - both can be used with serotonin 2A antagonists to treat refractory depression (trazodone, mirtazapine)

Question 5

dopamine

Answer 5

mesostiratal; SNpc: motor regulation, thalamic gating - implicated in PD, dysfunction here produces disabling motor and nonvoter symptoms

mesolimbic; VTA: memory, reward systems - implicated in addictive behaviors, overactivity here associated with positive symptoms of SZ, which respond well to dopamine-serotonin 2A antagonists (clozapine, quetiapine, risperidone)

mesocortical; VTA: EF, WM, top-down attention, motor initiation; dysfunction here produces negative symptoms of SZ, as well as dysexecutive syndrome and bradykinesia

tuberoinfundibular; hypothalamus: lactation, menstruation, sexual behavior

excitation/facilitation

reductions in dopaminergic NTmission in mesostriatal and mesocortical key players in producing motor and nonvoter issues of PD

Question 6

GABA

Answer 6

widely distributed

inhibitory (counteracting inhibitory input to same areas as other NT)

neuromodulatory, memory, anxiety/arousal

anti anxiety drugs act to enhance GABA-ergic NTmission, offsetting strong excitatory influences

Question 7

glutamate

Answer 7

widely distributed

post-synaptic excitation; most abundant excitatory

excitatory functions; key role in learning and memory; glutamatergic NMDA receptor implicated in processes of long-term potentiation and synaptic plasticity/neurogenesis - key to dev of new experience-dependent memories

excess glutamatertgic activity can lead to excitotoxicity and cell death - part of ischemic cascade implicated in stroke and ND diseases like AD, ALS, also in medical events like hypoglycemia and status epilepticus

memantine (NMDA receptor antagonist) used to treat AD - selectively inhibits pathological aspects of glutamatergic activation while preserving physiological activation of NMDA receptors, thus restoring LTP