Neurotransmission and CNS drugs Flashcards
(21 cards)
What are neurons?
Neurons are specialised cells that transmit electrical and chemical signals between the brain and body.
What are the three main types of neurons?
Sensory neurons (carry signals to CNS), Interneurons (connect sensory and motor), Motor neurons (carry signals to muscles/glands).
What is the role of dendrites in neurons?
Dendrites receive incoming signals.
What is the function of the cell body (soma)?
The cell body processes information.
What does the axon do?
The axon transmits signals away from the soma.
What is the resting state (polarisation) of a neuron?
Na⁺ is outside the cell body, and K⁺ is inside the neuron, maintained by the Na⁺/K⁺ ATPase pump.
What occurs during action potential (depolarisation)?
Na⁺ rushes in and K⁺ rushes out, generating an electrical impulse.
How do sodium/potassium ions move in and out of the neuron?
Active transport via sodium/potassium ATPase pumps maintains ion gradients.
What is the mechanism of neurotransmitter release?
Vesicles release neurotransmitters into the synaptic cleft via exocytosis.
What happens to neurotransmitters after release?
They can bind to receptors, diffuse out, degrade by enzymes, or be reuptaken by transporters.
What are the processes involved in neurotransmission?
Biosynthesis, storage, transport, docking, release, signaling, metabolism, and uptake.
How do drugs affect neurotransmission?
Drugs can enhance/inhibit synthesis, storage, release, receptor binding, metabolism, and reuptake.
What are ionotropic receptors?
Ligand-gated ion channels that allow ion flow upon binding with specific neurotransmitters.
What is the role of voltage-gated sodium channels?
They are essential for action potential generation by allowing Na⁺ ions to flow into the cell.
What is the function of GABA?
GABA is an inhibitory neurotransmitter that hyper-polarises neurons.
What are metabotropic receptors?
They regulate intracellular pathways via second messengers.
What is the blood-brain barrier (BBB)?
A network of vessels that forms a structural and chemical barrier between the brain and systemic circulation.
What are the key differences between brain and general capillaries?
General capillaries are fenestrated, while brain capillaries are not, affecting solute diffusion.
What is the mechanism of action of SSRIs?
They inhibit the reuptake of serotonin, increasing its availability in the synaptic cleft.
How does reserpine affect neurotransmission?
It depletes noradrenaline stores by inhibiting vesicular monoamine transporters.
What is the role of allosteric modulators?
They enhance or inhibit receptor function by binding to a non-active site.
