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Physiology 2: neuro > Monoamines > Flashcards

Flashcards in Monoamines Deck (73)
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1
Q

Neuromodulation

A

The physiological (Links to an external site.) process by which a given neuron (Links to an external site.) uses one or more chemicals to regulate diverse populations of neurons.

2
Q

Neuromodulators

A

Neurotransmitters that diffuse through neural tissue to affect slow-acting receptors of many neurons.

3
Q

Locus Coeruleus

A

It is a nucleus (Links to an external site.) (site of brain synthesis of noradrenalin) in the pons (Links to an external site.) of the brainstem (Links to an external site.) involved with physiological (Links to an external site.) responses to stress (Links to an external site.) and panic (Links to an external site.).

4
Q

Raphe Nuclei

A

A collection of nuclei of neurons in the brainstem that produce serotonin.

5
Q

Basal Forebrain Complex

A

Located in the forebrain to the front of and below the striatum. They include the nucleus accumbens, nucleus basalis, diagonal band of Broca, substantia innominata, and the medial septal nucleus. Rich in cholinergic neurons

6
Q

Hallucinogens

A

Compounds/drugs which produce hallucinations (e.g. LSD, Psilocybe)

7
Q

Stimulants

A

a drug that produces a temporary increase in psychomotor activity and usually induce feelings of euphoria, alertness and self-confidence (e.g. cocaine, amphetamine)

8
Q

4 main modulatory systems

A

– Noradrenergic Locus Coeruleus
– Serotonergic Raphe Nuclei
– Dopaminergic Substantia Nigra and Ventral tegmental Area
– Cholinergic Basal Forebrain and Brain Stem Complexes

9
Q

4 system principles for the modulatory system

A

– Small set of neurons at the core
– Arise from brain stem
– One neuron influences many others
– Synapses release transmitter molecules into the extracellular fluid

10
Q

5-HT1

A

Inhibits Adenylyl cyclase

11
Q

5-HT2

A

Stimulates phospholipase C

12
Q

Dopamine D1

A

Stimulates Adenylyl cyclase

13
Q

Dopamine D2

A

Inhibits Adenylyl cyclase

14
Q

Noradrenaline beta

A

Stimulates Adenylyl cyclase

15
Q

Noradrenaline alpha 1

A

Stimulates phospholipase C

16
Q

Noradrenaline alpha 2

A

Inhibits Adenylyl cyclase

17
Q

Behavioural effects of modulatory systems

A

Mood, memory, reward, movement, motivation

18
Q

Noradrenaline causes

A
  • Arousal
  • Wakefullness
  • Exploration and mood
  • (low NA in depressed)
  • Blood pressure
  • Addiction/gambling
19
Q

Hypothalamus

A

Hormones, sleep, body temperature, endocrine and autonomic controller)

20
Q

Locus coeules

A

known as ‘blue spot’ because of pigmentation. NA in this region makes the brain more responsive, increases information processing

21
Q

Regulation of NA

A

Post-synaptic
– Carry on the message
Pre-synaptic (autoreceptors)
– Usually inhibitory
– Negative feedback mechanism
• Reserpine-depletes NA stores by inhibiting vesicular uptake
• Amphetamine (indirect sympathomimetic)-enters vesicles displacing NA into cytoplasm, increase NA leakage out of neuron

22
Q

Noradrenaline

A
  • Reserpine-depletes NA stores by inhibiting vesicular uptake
  • Amphetamine (indirect sympathomimetic)-enters vesicles displacing NA into cytoplasm, increa NA leakage out of neuron
  • Cocaine-blocks NA re-uptake
23
Q

Amphetamine

A

Increase alertness and exploratory behaviour

24
Q

Where is there a lot of Noradrenaline

A

High density in brainstem, hypothalamus & medial temporal lobe

25
Q

Functions of Noradrenaline

A
  • Arousal, wakefullness, exploration and mood (low NA in depressed patients)
  • Blood pressure regulation, (antihypertensive e.g. clonidine 2)
  • (Addiction/gambling)
26
Q

Functions of Noradrenaline

A
  • Arousal, wakefulness, exploration and mood (low NA in depressed patients)
  • Blood pressure regulation, (antihypertensive e.g. clonidine 2)
  • (Addiction/gambling)
27
Q

NA and cell bodies

A

cell bodies in brain stem largest group in locus coeruleus (LC) in the pons. LC neurons silent during sleep and activity increases with arousal – especially in response to unfamiliar and threatening stimuli. Low NA – low arousal – found in depressed patients

28
Q

What is NA main cell body?

A

Locus Coeruleus

29
Q

NAergic pathways & Daergic and the limbic system

A

Play role in the reward system and are implicated in drug dependence

30
Q

NAergic synapses

A

Found in medulla form part of the baroreceptor reflex pathway – regulation of blood pressure

31
Q

Amphetamine-like drugs

A

Release catecholamines and increase wakefulness, alertness and exploratory behaviour.

32
Q

Dopamine is involved in what?

A

Movement
Reward
Inhibition of prolactin release
Memory consolidation

33
Q

Diseases associated with dopamine

A
Parkinson’s Disease
Schizophrenia
Addiction
Emesis
ADHD
34
Q

Tuberohyphyseal pathway

A

Prolactin secretion

35
Q

VTA – mesocorticolimbic dopamine system

A

DA projection from midbrain. Important in addiction and schizophrenia / psychoses

36
Q

Substantia nigra

A

Projects to the striatum important for control / initiation of voluntary movement

37
Q

Main dopamine pathways

A
  • Substantia nigra to basal ganglia (Parkinson’s disease)

* Midbrain to limbic cortex (schizophrenia)

38
Q

Other functions of dopamine

A

Movement, addiction, stereotypy, hormone release, vomiting

39
Q

5-HT3 (serotonin)

A

Ion channel
PNS
neuronal excitat

40
Q

Serotonin

A

5- HT

41
Q

What type of receptors is serotonin receptors?

A

14 subtypes

All G-protein coupled except 5-HT3

42
Q

5-HT1

A

Limbic system mood, migraine

43
Q

5-HT2 (5-HT2A)

A

Excitatory, hallucinogenic, limbic system & cortex

44
Q

5-HT3

A

Excitatory medulla vomiting

45
Q

5-HT4

A

Presynaptic facilitation (ACh) Cognitive enhancement

46
Q

5-HT6 and 5-HT7

A

Novel targets, cognition, sleep

47
Q

Main functions of serotonin

A
  • Mood
  • Psychosis
  • Sleep/wake (5-HT linked to sleep, 5-HT2 antagonists inhibit REM sleep)
  • Feeding behaviour
  • Pain, migraine (5-HT inhibits pain pathway, synergistic with opioids)
  • Vomiting,
48
Q

Disorders related to serotonin

A

(anxiety/depression)
(5HT antagonism antipsychotic)
(5HT2A antagonist increase appetite, weight gain; antidepressants decrease appetite

49
Q

Dopamine

A

DAT (on dopamine neurons)

50
Q

5-HT

A

SERT (on 5-HT neurons)

51
Q

NA

A

NET (on noradrenaline neurons)

52
Q

Glutamate

A

EAAT1 (mostly on astrocytes)

53
Q

Dopamine

A

vMAT2 (into vesicles)

54
Q

Monoamine transporters

A

12 TMDs
Both ends intracellular
Pump monamines in neuron
DA, NA, 5HT transporters

55
Q

Acetylcholine is involved in part 1

A
  • Memory, learning
  • Motor control (striatum)
  • Reward
  • Arousal
  • Alzheimer’s
  • Pain
56
Q

Acetylcholine is involved in part 2

A
  • Addiction
  • Epilepsy (nAChR genes)
  • Schizophrenia
  • ADHD
  • depression
  • anxiety,
57
Q

Functions with acetylcholine

A
  • Arousal
  • Epilepsy (mutations of nAChR genes)
  • Learning and memory (KO mice)
  • Motor control (M receptors inhibit DA), pain, addiction
  • Involved in schizophrenia, ADHD, depression, anxiety, Alzheimers
58
Q

Histamine

A

– H1 (arousal) and H3 (presynaptic / constitutively active)
– Functions: sleep / wake, vomiting
– Purines
– Adenosine (A1, A2A/2B) and ATP (P2X)
– Functions: sleep, pain, neuroprotection, addiction, seizures, ischaemia, anticonvulsant
– Neuropeptides
– Opioid peptides (kappa, delta. mu)
– Tachykinins (Substance P, neurokinin A & neurokinin B)
• NK1 (Substance P), NK2 (neurokinin A), NK3 (neurokinin B)

59
Q

Proopioimelanocortin (Beta-endorphin)

A

MOP and DOP

60
Q

Proenkephalin (Enkephalins)

A

DOP

61
Q

Prodynorphin

Dynorphins

A

KOP

62
Q

Pronociceptin

Nociceptin/OFQ

A

NOP

63
Q

Melatonin

A
  • MT1, MT2 receptors

- involved in sleep regulation, circadian rhythmicity, agonists for jet lag and insomnia

64
Q

Lipid mediators

A
  • Products of conversion of eicosanoids to endocanabinoids
    • act on CB1 (inhibit GABA, glutamate release)
    • involved in vomiting (CB1 agonist block it, MS, pain, anxiety, weight loss/rimonabant CB1 antogonist)
65
Q

Drugs interacting with the diffuse system

Psychostimulants: Amphetamine

A
  • Amphetamine-like drugs (methylphenidate & MDMA)
  • Release cytosolic monoamines (DA)
  • Prolonged use neurotoxic
  • Degeneration of amine-containing nerve terminals, cell death
66
Q

Pharmacological effects of Psychostimulants: Amphetamine

A
  • increase alertness and locomotor stimulation (increase aggression)
  • Euphoria/excitement
  • Stereotyped behaviour
  • Anorexia
  • decrease physical and mental fatigue (improves monotonous tasks)
  • Peripheral sympathomimetic actions (increase blood pressure & decrease gastric motility)
  • Confidence improves/lack of tiredness
67
Q

Therapeutic uses of Psychostimulants like Amphetamine

A

ADHD (methylphenidate), appetite suppressants, narcolepsy

68
Q

Cocaine

A

Blocks catecholamine reuptake

• (increases DA, stimulant effect)

69
Q

Cocaine Pharmacological effects

A
  • Euphoria
  • Locomotor stimulation
  • Fewer stereotyped behaviours than amphetamine
  • Heightened pleasure
  • Lower tendency for delusions, hallucinations and paranoia
70
Q

Cocaine Pharmacokinetics

A
  • HCl salt, inhaled and i.v. administration
  • Nasal inhalation less intense, leads to necrosis of nasal mucosa
  • Freebase form (‘crack’), smoked, as intense as i.v route
71
Q

MDMA

A

Inhibits monoamine transporters (mainly 5-HT)
Large increase 5-HT (followed by depletion)
Increases 5-HT linked to psychotomimetic effects
Increases DA linked to euphoria (followed by rebound dysphoria)

72
Q

LSD, Psylocybin

A

• Hallucinogenic effect by acting on 5HT2 receptors

73
Q

Psychostimulants

A
  • Also increase 5HT and NA

* Cocaine block DAT, NET, SERT