Neurotransmitters Flashcards

1
Q

Method of termination for glutamate

A

Re-uptake

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2
Q

Methods of glutamate synthesis in brain

A

Glucose via TCA cycle

Glutamine

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3
Q

Types of Glutamate Receptors

A

NMDA
AMPA
Kainate
(All ionotropic)

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4
Q

Permeability of NMDA receptors

A

Sodium, like all receptors, but especially the second messenger calcium

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5
Q

NMDA Receptor Activation Mechanism

A

Voltage and ion gated.

Depolarization is necessary to remove the magnesium ion that clogs the pore, and then an agonist (glutamate) and co-agonist(glycine or d-serine) must bind for activation

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6
Q

Key effects of Calcium entry through NMDA channels

A

Synaptic plasticity: Long-term potentiation which is thought to underlie memory formation

Excitotoxicity: Excessive calcium entry leads to cell death in some cases

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7
Q

Clinically useful glutamatergic drugs

A

Ketamine: Binds to the Magnesium binding site and inhibits NDMA activation

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8
Q

GABA Localization

A

Interneurons throughout the brain

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9
Q

Types of GABA receptors

A

GABAa- Allows Cl- entry, leading to hyperpolarization

GABAb- causes K+ to leave (efflux), also leading to hyperpolarization

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10
Q

Glycine Localization

A

Brainstem and spinal cord

In the forebrain, it serves as an important co-agonist for NMDA receptors

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11
Q

Catecholamine Biosynthesis Pathway

A

Tyrosine converted to DOPA via tyrosine hydroxylase

DOPA converted to Dopamine by DOPA decarboxylase

Dopamine converted to norepinephrine via Dopamine B-hydroxylase

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12
Q

3 Important Dopamine Systems in the Brain

A

Nigrostriatal

Mesocortical/mesolimbic

Tuberoinfundibular

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13
Q

Nigrostriatal System (Cell origin/function)

A

Cells origin in the substantia nigra and project to the striatum

Key role in movement initiation

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14
Q

Mesocortical/Mesolimbic System

A

Cells originate in ventral tegmental area and prject to prefrontal cortex/ventral striatum

Part of “reward pathway”, so important role in regulation of mood and drug abuse

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15
Q

Tuberoinfundibular System (Cell origin and function)

A

Cells originate in hypothalamus and project to the pituitary

Controls prolactin secretion (regulates lactation)

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16
Q

Norepinephrine Localization in the brain

A

Noradrenergic neurons are in the locus coeruleus, and account for the majority of adrenergic input to the limbic system

17
Q

Function of Noradrenergic Pathways

A

Attention, arousal, vigilance, mood regulation

18
Q

Serotonin Biosynthesis Pathway

A

Tryptophan to 5-HTP via tryptophan hydroxylase (rate-limiting enzyme)

5-HTP to serotonin via Aromatic L-amino acid decarboxylase

19
Q

Serotonin Inactivation Mechanism

20
Q

Serotonin Pathways in the Brain

A

Median raphe nucleus contains serotonin cell bodies that innervate the parts of the limbic system, which is in the forebrain

21
Q

Histamine Localization in the Brain

A

Tuberomammillary nucleus, located in the posterior hypothalamus

22
Q

Mechanism of inactivation for histamine

23
Q

Function of histamine in the brain

A

Arousal (hence, antihistamines are used to treat insomnia)

24
Q

Acetylcholine Biosynthesis

A

Choline and Acetyl-Coa are combined by choline acetyltransferase

Choline uptake is the rate-limiting step

25
Inactivation of Acetylcholine Mechanism
Acetylcholinesterase
26
Cholinergic Pathways in the Brain
Neurons in basal forebrain structures, such as: Medial Septal Nucleus Nucleus Basalis of Meynert
27
Functions of Cholinergic Pathways in the Brain
Learning and Memory
28
Effects of Opioids on other pathways
Plays a key role in analgesia in both ascending and descending pathways Also modulates dopaminergic reward pathways
29
Ubiquitous Brain Signaling Molecules
Adenosine Endocannabinoid
30
Primary Actions of Adenosine
Inhibit release of excitatory neurotransmitters, inhibits postsynaptic effects (Note: caffeine is an adenosine receptor antagonist)
31
Endocannabinoids Primary Mechanism
Inhibit neurotransmitter release (retrograde neurotransmitter)