Monoamines Flashcards
Neuromodulation
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.
Neuromodulators
Neurotransmitters that diffuse through neural tissue to affect slow-acting receptors of many neurons.
Locus Coeruleus
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.).
Raphe Nuclei
A collection of nuclei of neurons in the brainstem that produce serotonin.
Basal Forebrain Complex
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
Hallucinogens
Compounds/drugs which produce hallucinations (e.g. LSD, Psilocybe)
Stimulants
a drug that produces a temporary increase in psychomotor activity and usually induce feelings of euphoria, alertness and self-confidence (e.g. cocaine, amphetamine)
4 main modulatory systems
– Noradrenergic Locus Coeruleus
– Serotonergic Raphe Nuclei
– Dopaminergic Substantia Nigra and Ventral tegmental Area
– Cholinergic Basal Forebrain and Brain Stem Complexes
4 system principles for the modulatory system
– Small set of neurons at the core
– Arise from brain stem
– One neuron influences many others
– Synapses release transmitter molecules into the extracellular fluid
5-HT1
Inhibits Adenylyl cyclase
5-HT2
Stimulates phospholipase C
Dopamine D1
Stimulates Adenylyl cyclase
Dopamine D2
Inhibits Adenylyl cyclase
Noradrenaline beta
Stimulates Adenylyl cyclase
Noradrenaline alpha 1
Stimulates phospholipase C
Noradrenaline alpha 2
Inhibits Adenylyl cyclase
Behavioural effects of modulatory systems
Mood, memory, reward, movement, motivation
Noradrenaline causes
- Arousal
- Wakefullness
- Exploration and mood
- (low NA in depressed)
- Blood pressure
- Addiction/gambling
Hypothalamus
Hormones, sleep, body temperature, endocrine and autonomic controller)
Locus coeules
known as ‘blue spot’ because of pigmentation. NA in this region makes the brain more responsive, increases information processing
Regulation of NA
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
Noradrenaline
- 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
Amphetamine
Increase alertness and exploratory behaviour
Where is there a lot of Noradrenaline
High density in brainstem, hypothalamus & medial temporal lobe
Functions of Noradrenaline
- Arousal, wakefullness, exploration and mood (low NA in depressed patients)
- Blood pressure regulation, (antihypertensive e.g. clonidine 2)
- (Addiction/gambling)
Functions of Noradrenaline
- Arousal, wakefulness, exploration and mood (low NA in depressed patients)
- Blood pressure regulation, (antihypertensive e.g. clonidine 2)
- (Addiction/gambling)
NA and cell bodies
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
What is NA main cell body?
Locus Coeruleus
NAergic pathways & Daergic and the limbic system
Play role in the reward system and are implicated in drug dependence