Neural signalling - synaptic transmission Flashcards
What are neonicotinoids?
Synthetic compounds similar to nicotine commonly found in pesticides
How do neonicotinoids affect synaptic transmission in insects?
They block synaptic transmission at cholinergic synapses by binding to acetylcholine receptors
What is the nature of the binding of neonicotinoids to acetylcholine receptors?
The binding is irreversible
What is the consequence of acetylcholine receptors being blocked by neonicotinoids?
Acetylcholine is unable to bind, stopping impulses from being transmitted across synapses
What are the effects of neonicotinoids on insects?
They lead to paralysis and death in insects
Why are neonicotinoids considered suitable as pesticides?
They are not toxic to humans and other mammals
What is the difference in cholinergic synapses between insects and mammals?
A much larger proportion of synapses in insects are cholinergic compared to mammals
How do neonicotinoids compare in binding strength to acetylcholine receptors in insects versus mammals?
They bind much more strongly to acetylcholine receptors in insects
What is a significant controversy regarding neonicotinoid pesticides?
Their impact on essential pollinators such as bees
What is the mechanism of action of cocaine?
It blocks the reuptake of neurotransmitters into the presynaptic knob
Which neurotransmitter does cocaine primarily affect?
Dopamine
What happens to dopamine levels in the synapses when cocaine is used?
Dopamine builds up in the synapses
What additional neurotransmitters does cocaine block?
Serotonin and norepinephrine
What is the result of increased dopamine receptors in regular cocaine users?
Increased sensitivity and depression once dopamine levels return to normal
What are inhibitory postsynaptic potentials?
They prevent the generation of an action potential in a postsynaptic neurone
How can a neurotransmitter inhibit an impulse?
By opening gated potassium ion channels in the membrane
What occurs when potassium ions diffuse out of the cell body?
The postsynaptic neurone becomes more negatively charged or hyperpolarised
What happens when a neurone is hyperpolarised?
The threshold will not be reached, and an action potential cannot be triggered
What happens when both excitatory and inhibitory synapses stimulate a motor neurone?
The effects cancel out, and no action potential is generated
Why are inhibitory synapses important in the nervous circuit?
They prevent random impulses and allow for specific pathways to be stimulated
What is the role of inhibitory pathways in skill development?
They help refine uncontrolled movements in skills like painting and drawing
What is summation in the context of neurotransmitter effects?
The process where multiple impulses can be added together to generate an action potential
What are the two types of summation?
- Temporal
- Spatial
What is temporal summation?
When multiple impulses arrive in quick succession to generate an action potential
