1.3.1 CNS Neurotransmitters Flashcards

1
Q

Describe the synthesis of serotonin.

A

– made from tryptophan → 5-HT

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2
Q

Some drugs can do what to histamine receptors?

A

-Inhibition of histaminergic receptors is responsible fro the sedative adverse effects of many drugs

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3
Q

What is the synthesis of Dopamine?

A

tyrosine → DOPA → Dopamine

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4
Q

What is the synthesis of Norepinephrine?

A

from tyrosine → DOPA → dopamine → NE → Epi

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5
Q

What are some examples of indirect gating?

A
  • Gs: stimulates AC
  • Gi: inhibits AC & opens K channel
  • Gq: stimulates phospholipase C
  • Go: closes Ca channel
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6
Q

What are the characteristics of chemical synapses?

A
  • Slower and more complex signaling than electrical synapses
  • Important for the function of most CNS active drugs
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7
Q

What is the importance of glutamate?

A

most predominant excitatory NT in CNS

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8
Q

Drugs that target opoid receptors are used for?

A

-Drugs targeting opioid receptors are used to treat pain

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9
Q

What are the receptors for glutamate?

A

NMDA (blocked by Mg)

AMPA (pain)

kainate

GPCR

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10
Q

Describe the synthesis of GABA.

A

-Formed by decarboxylation of glutamate

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11
Q

What is indirect gating in regards to chemical synapses?

A
  • Indirect Gating: Non-Channel Linked Receptors
  • Binding of nt activates second messenger pathways via G-proteins (metabotropic)
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12
Q

How is acetylcholine synthesized?

A
  • Combination of acetyl CoA (from mitochondria) and choline (from diet)
  • Catalyzed by choline acetyltransferase (ChAT)
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13
Q

Describe the termination of GABA

A

Reuptake

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14
Q

How can stimulants and amphetamines affect the action of norepinephrine?

A

Amphetamines - can cause increased release of norepinephrine

Stimulants (cocaine) - cause decreased reuptake of norepinephrine

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15
Q

How is norepinephrine terminated?

A

Reuptake

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16
Q

What is the sequence of events in a chemical synapse?

A
  • Release of NT from pre-synaptic terminal requires calcium
  • Voltage-dep calcium channels open when AP depolarizes them
  • Transmitter diffuses through synaptic cleft to post-synaptic neuron
  • Post-synaptic response depends on the type of receptors present
17
Q

What are the receptors for norepinephrine?

A

Adrenergic

α1-excitation, increased IP3:DAG

α2 – inhibitory at pre-synapse

β- GPCR (increased cAMP)

18
Q

Alzheimers disease is related to cholinergic action?

A
  • reduction in the activity of cholinergic neurons
  • drugs are used in AD to increase cholinergic activity
19
Q

What are the characteristics of nuclear receptors?

A
  • Binding of a ligand to a nuclear receptor will cause a downstream change in gene expression
  • This modulation of gene expression may be either to up or down regulate transcription
20
Q

What is the role of serotonin?

A
  • Serotonergic mechanisms modulate anger, aggression, body temp, mood, sleep, human sexuality, appetite and metabolism
  • Also have potential to stimulate emesis
21
Q

What are the receptors acetylcholine and what is their importance?

A
  • Muscarinic – Metabotropic receptors important in glandular secretion (M1 is excitatory and M2 is inhibitory)
  • Nicotinic – Ionotropic receptors important in motor end plate function (increased conductivity to cations)
22
Q

How is the effect of acetylcholine terminated?

A
  • Metabolism by acetylcholinesterase (AChe) on postsynaptic membrane (choline recylced)
  • Very short half life
23
Q

What are some examples of neurotransmitters that utilize direct gating?

A
  • Glutamate
  • ACh
  • GABA
  • Glycine
  • Serotonin
24
Q

What is the effect of serotonin on the different receptors? (Dont know if this is important)

A
  • Receptors
  • Metabotropic:
  • 5-HT 1A– Inhibitory
  • 5-HT 2A – Excitatory
  • Ionotropic:
  • 5-HT 3 – Excitatory
  • ↑ cation conductance
  • 5-HT 4 – Excitatory
  • ↓K conductance
25
Q

What is the role of dopaminergic receptor activation?

A
  • Dopaminergic receptors are responsible for reward and motivation, as well as many emotions like euphoria, orgasm, anger, addiction, love, and pleasure
  • Also important in the regulation of renal vascular flow
26
Q

Decreased GABA can lead to?

A

-Decreased GABA activity or increased glutamate activity can precipitate seizures (ex: in alcohol withdrawal)

27
Q

What is direct gating in regards to chemical synapses?

A
  • Direct Gating: Ligand-Gated Receptors
  • Binding of neurotransmitter opens or closes an ion channel within the receptor (ionotropic)
  • Activation results in a rapid change in postsynaptic membrane potential
28
Q

What are the characteristics of synaptic transmission?

A
  • Bridges synaptic gaps between neurons and their target cells
  • Rapid cell communication and long-term modulation
  • Drugs have enormous impact on this process
29
Q

What is the role of GABA?

A

-Major inhibitory neurotransmitter in the brain

30
Q

What is the role of histamine outside the brain?

A

-Histaminergic mechanisms are critical in peripheral inflammation (H1) and gastric acid secretion (H2)

31
Q

D2 (dopamine) receptor activation leads to?

A
  • D2 Receptors: inhibitory
  • Mechanism of effect depends on the location of the receptor:
  • Presynaptic: ↓ Ca Conductance
  • Postsynaptic: ↑K → ↓cAMP
32
Q

Glutamate over-excitation is involved in?

A

-Glutamatergic over-excitation of neurons is involved in both acute and chronic brain injury (high ca influx)

33
Q

SSRIs target what?

A

-reuptake transporters on presynaptic membrane

34
Q

What are the characteristics of gap junctions?

A

These are also electrical synapses

Extremely rapid cell communication

Links activity between adjacent cells

Drugs have minimal impact on this process

35
Q

What is acetylcholine?

A

Small nt released (Ca- dependent) in vesicles at presynaptic terminal, crossing synapse, and binding to cholinoceptors on postsynaptic membrane

36
Q

What is the use of adrenergic receptors?

A
  • Adrenergic receptors elevate mood and increase wakefulness and attention
  • Also have critical CV functions