Neuropharmacology introduction Flashcards
What are the 3 main systems in the CNS ?
- Sensory system - covered in neuro
- Motor system - covered in neuro
- Limbic system
What is the function of the limbic system ?
- Regulation of emotion, mood and behaviour
- Also involved in long-term memory and olfaction
Label the main components of the limbic system
In terms of the limbic system what is the major role of each the following:
- Hippocampus
- Amygdala
- Hippocampus - major role in memory formation
- Amygdala - important in regulating fear responses
Note smells are good at stimulating emotions or memories so the olfactory cortex is well represented in the limbic system
What are the 3 main working units of the CNS (components)?
- NEURONES
- NEUROGLIA
- EXTRACELLULAR SPACE
What is a neurone made up of and what is there function?
- Cell body (soma)
- Axon
- Dendrite
- Nerve terminal
Cell body = grey matter
Axon = white matter
To receive and transmit information
What are the 4 main types of neuroglia cells and their function
- Astrocytes - They hold neurones in place, regulate nutrients, modify neuronal signals and can regulate local blood flow
- Oligodendrocytes - produce myelin sheath to permit rapid electrical conduction
- Ependymal cells - line cerebral ventricles and are responsible for the manufacture of CSF
- Microglia - are the defense mechanism. Phagocytic cells of the brain.
What is a synapse ?
A junction between two nerve cells, consisting of a minute gap across which impulses pass by diffusion of a neurotransmitter.
What are the different neurotransmitters we need to know about?
- Amino acid neurotransmitters - Glutamate and GABA (gamma-aminobutryric acid)
- Acetylcholine (ACh) - cholingeric system
- Noradrenline/ norepinephrine
- Dopamine
- Serotonin (5-hydroxytryptamine - 5HT)
What is the function of glutamate (glutamic acid)?
It is the main excitatory neurotransmitter in the brain, involved in memory & learning
What can oversupply of glutmate result in ?
Can result in overstimulation of the brain resulting in migraines or seizures, this is why some people avoid MSG (monosodium glutmate) in food
What is the function of the neurtransmitter GABA ?
It is the main inhibitory neurotransmitter in the brain
What can undersupply of GABA result in ?
Seizures, tremors and insomnia
What type of drugs are aminoacid neurotransmitters often the target for ?
general anaesthetics, anti-epileptics, anxiolytics (anti-anxiety)
Can amino acid neurotransmitters cross the blood brain barrier ?
No - so need to be synthesised in the CNS from precursors such as glucose etc
What is the main functions of acetylochline ?
- Motor control
- Cognitive function - Learning and memory and attention
What problems can arise when there is imbalances in acetylocholine ?
Acetylocholine producing neurones degenerate as alzhimers disease progresses
Along with being present in the CNS where is acetylocholine also present ?
In the PNS
What is the main function of noradrenaline/ noepinephrine ?
Helps control alertness and arousal (cell producing NA particularly sensitive to noxious or stressful stimuli), also emotion
What can problems in undersupply of NA result in ?
- Depressed mood
- Cause ADHD-like attention problems
What is the functions of dopamine ?
- Involved in motor control (movement)
- Motivation/reward
- Prolactin release from pituitary gland
- Also involved in learning, attention and emotion
What is the function of serotonin ?
- Mood
- sleep
- feeding behaviour and sensory perception (hallucinations and analesgia - relief of pain)
What can problems in serotinin levels result in ?
- Undersupply linked to depression
- Some anti-depressants raise serotinin levels
What are the main neuropeptides which act also as neurotranmistters and what is there role in?
Substance P and opioid peptides found in spinal cord and higher brain centres
Play a role in perception of pain
What is the function of the blood brain barrier and why is it more difficult for things to pass through it ?
The blood brain barier (BBB) is a control system to preserve homeostasis in the nervous system, facilitating the entry of necessary metabolites, but blocking the entry or facilitating the removal of unnecessary metabolites or toxic substances
BBB have no fenestration (holes) - has tight junctions between cells
In general what types of drugs get through and which don’t (throught the BBB)?
- Lipid soluble get through
- Water soluble don’t
