lecture 6: Neurons, neurotransmitters, drugs and mental function Flashcards
synapse
- the means by which neurons communicate with other neurons and muscle fibres
how does the communication between neurons change
it changes from electrical to chemical at the synapse and then back to electrical
what is the gap between the axon terminal and dendrite called
synaptic cleft
neurotransmitter
- when an action potential arrives at an axon terminal a special chemical called a neurotransmitter is released at the synaptic cleft
- receptors at the post synaptic neuron respond to the neurotransmitter and generate a graded potential
synaptic cleft
the small space between the axon terminal of a presynaptic neuron and the dendrite of a postsynaptic neuron where chemical signals are released and diffuse to transmit signals across the synapse
vesicles
- key organelles in neurotransmitter release at synapses
- small membrane bound sacs that store and release neurotransmitters at synapses, facilitating communication between neurons
drugs can have an effect by altering neurotransmitter ..
- synthesis
- storage
- release
- binding
- reuptake
synthesis
some drugs might increase or reduce amount of drug that is available
storage
chemical has to be stored in the vesicles, some drugs make these vesicles leaky so that when the vesicle releases the neurotransmitter, there is less neurotransmitter
release
process of vesicles going to the membrane and releasing the neurotransmitter, some drugs interrupt this
binding
molecule interacts with the receptors on the dendrite, some drugs block these receptors so the molecule is floating around but there are no receptors for it
reuptake
impact re uptake mechanism, so chemical sits in synapse for longer, going to get a signal that is stronger than it normally would be
agonists
drugs that bind to a receptor of a cell and trigger a response
- an agonist often mimics the action of a naturally occurring substance
- an indirect agonist enhances the release or action of an endogenous neurotransmitter
antagonist
drugs that block or suppress agonist mediated responses
what are the advantages of having multiple chemicals
can make sure one particular signal doesnt interact with some other signal
- signals will be picked up by different systems
acetylcholine
- example of a neurotransmitter in the brain
- has receptors in the CNS for this, appears to be involved in processes to do with memory
- neurons which interact with the muscle fibres causing them to contract, always transmitted through ACH
dopamine
- a crucial neurotransmitter and hormone in the brain, playing a vital role in reward, motivation, movement, and other functions
parkinsons disease
- affects approx 1% of the population
- caused by changes in neurotransmission
symptoms: - tremors
- muscular rigidity
- slowness of movement
- postural instability
- involuntary shifts of posture (dystonia and dyskinesia)
- shuffling, wide based gait with forward leaning posture
- leading to festination
schizophrenia
- impacts 1% of the population
positive symptoms: - delusions
- hallucinations
- disorganised thinking
negative symptoms: - blunted affect
- poverty of speech and thought
- apathy
cognitive symptoms: - poor working memory
- disruption in executive function and attention
deep brain stimulation
- generating little electrical pulses, artificially causes neurons to generate APs, can cause certain neurons in the deep part of brain to be activated and send APs which can suppress parkinsons
