neuropharmacology (week 10-12)

ion channels (act like a gate for ions. When neurotransmitter binds to it, it opens up and allows certain ions to flow in, usually resulting in an action potential), and g-protein coupled (when a neurotransmitter binds, it turns GDP into GTP, which energises a second messenger inside the cell which binds to another receptor in the cell)

neurotransmitters and their receptors bind like a lock and key. Their physical makeups fit together, and the receptors are highly specific, meaning only certain transmitters can activate certain receptors

A neurotransmitter strictly from synapses which diffuses across a cleft to effect one or two postsynaptic neurons, a muscle cell, or other effector cell, and is ither excitatory or inhibitory. Neuromodulators effect groups of neurons or effector cells with the correct receptors. Must not be from a synapse, and usually works with secondary modulators, and can provide longer effects, often changing the receptivity of neurons.

can affect the presynaptic neuron by impacting neurotransmitter release, can affect the postsynaptic neuron by altering neurotransmitter function (firing pattern or excitability), or changes neural function or structure, impacting synaptic plasticity

they are found deep in the brain, in some nucleus, and are transported through various long neurons

neurotransmitters are synthesised in the cell body of the neuron, and then they are slowly transported through the axons to the synapse, however, release is fast, because they sit in the synapse ready.

drugs can mimic neurotransmitters by being similarly shaped, meaning that their either antagonise (prohibit binding of neurotranmitters resulting in no stimulation) or agonise (overstimulate) the receptors, resulting in the effect felt by the user. Drugs can affect all stages of neurotransmitters.

synthesis, release from synaptic vesicles, binds to receptors, +/- influence on postsynaptic neuron, broken down by enzymes, reuptake of transmitter, formation and storage in synaptic vesicles. Drugs can effect all stages.

both true neurotransmitters, released by presynaptic neuron, directly effecting the likelihood of neurons firing.

it is synthesised from glutamine, which is released from neighbouring cells. Note, glutamate can be turned into GABA and GABA can be turned into glutamate.

4 major types, 3 ion channels (NMDA receptor, AMPA receptor, Kainate receptor).

complex and only works if glycine is bound and magnesium is not. Alcohol is the most common antagonist, and also agonises GABA (inhibitory). PCP and ketamine also antagonise this receptor, causing dissociative hallucination.

it is an inhibitory neurotransmitter which reduces the likelihood that neurons fire for their non-preferred stimulus. They do this by increasing the selectivity, not determining what signals the glutamate chooses

Glutamate can be turned into GABA and GABA can be turned into glutamate.

gereralised (most brain areas), partial (specific brain regions, can ble split into simple (change of consciousness, but no loss of consciousness), and complex (loss of consciousness)).

mostly genes involved in seizures are to do with incorrect ion channels. Most causes of seisures though, are due to abnormal brain tissue

Seizures

ingested as Thyrocine amino acid in food, converted by Thyrocine hydroxylase to L-Dopa, then turned into Dopamine by amino acid decarboxylase. (note its broken down by dopamine beta hydroxylase into noradrenaline)

motor function, and reward systems in the brain (important in coding cost benefit for the neural systems)

When an unexpected reward is given, there is a spike in dopamine. When the reward is habituated to a noise, the dopamine occurs after the noise, not after the reward. If the reward is not given after the signal, after the lack of reward, there is a suppression of dopamine

Episodic Future thinking, and difficulties in it are associated with difficulties in appreciating and applying knowledge and benefits of delayed gratification.

when paired with a beep, unlike normal rewards, dopamine drugs like cocaine still release high levels of dopamine when the reward comes, meaning it perceives the drug as better than expected, cycling into addiction. Normal rewards release no extra dopamine when habituated to a bell.

drugs initiate “wanting” and cravings in addicted person,

dopamine is broken down by dopamine beta hydroxylase into noradrenaline