w1 L3 neurotransmission

What are the main classifications of signaling molecules in the nervous system?

Neurotransmitters, neuromodulators, and neurotrophic factors.

Define a neurotransmitter.

A neurotransmitter is a chemical messenger that directly transmits signals between neurons at a synapse, causing a rapid and specific response.

What is a neuromodulator?

A neuromodulator influences a wider group of neurons by modulating their activity, affecting the overall neural network rather than a single target.

How do neurotransmitters affect their target neurons?

They directly excite or inhibit a target neuron at a specific synapse.

What are ionotropic receptors associated with?

Fast neurotransmission using multimeric receptors that incorporate ion channels.

Give examples of fast neurotransmitters.

Nicotinic acetylcholine receptor (nAchR) is an example.

Define the roles of neuromodulators in neurotransmission.

Neuromodulators enhance the excitatory/inhibitory responses of ion-channel receptors and can limit or prolong the effects of neurotransmitters.

What is the synapse?

A synapse is the junction where two neurons communicate with each other, allowing information to pass.

What is an EPSP?

An excitatory postsynaptic potential (EPSP) is a temporary increase in postsynaptic membrane potential, making the neuron more likely to fire an action potential.

What is an IPSP?

An inhibitory postsynaptic potential (IPSP) is a temporary decrease in postsynaptic membrane potential, making the neuron less likely to fire an action potential.

What is the resting membrane potential (RMP)?

The resting membrane potential is the voltage difference across the cell membrane when the neuron is at rest, typically around -70mV.

What process do neurotransmitters use to return to their presynaptic terminal?

Reuptake is the process in which neurotransmitters are taken back into the presynaptic terminal.

Name one major excitatory neurotransmitter in the CNS.

Glutamate.

What is the function of GABA in the neurotransmission process?

GABA is the major inhibitory neurotransmitter in the CNS, reducing neuronal excitability.

What testing method is used to assess nerve injuries?

Nerve conduction studies (NCS).

What role do calcium channels play in neurotransmission?

Calcium channels allow calcium ions to enter the presynaptic terminal, facilitating neurotransmitter release.

What happens during the absolute refractory period?

During the absolute refractory period, voltage-gated Na+ channels are inactivated and cannot be re-activated.

How does repolarization occur after an action potential?

Repolarization occurs through the opening of voltage-gated K+ channels which allows potassium ions to flow out of the neuron, returning the membrane potential to resting state.

What might be a symptom of peripheral neuropathy?

Weakness or numbness in arms and legs due to nerve damage.

What are the functional classifications of neurotransmitters?

Neurotransmitters can be classified as either excitatory or inhibitory based on their effects on postsynaptic neurons.

Explain the role of retrograde signaling in synaptic communication.

Retrograde signaling involves the transmission of signals from postsynaptic neurons back to presynaptic neurons, modulating neurotransmitter release and synaptic strength.

What is the significance of the blood-brain barrier in neurotransmission?

The blood-brain barrier protects the brain from harmful substances, but it also limits the delivery of many neurotransmitters and drugs to neuronal tissue.

Describe the mechanisms of long-term potentiation (LTP).

LTP is a persistent strengthening of synapses based on recent patterns of activity, which increases synaptic transmission efficiency, often mediated by NMDA receptor activation.

How do different neurotransmitters affect mood and behavior?

Neurotransmitters like serotonin, dopamine, and norepinephrine play critical roles in regulating mood, reward pathways, and emotional responses.

What are the implications of neurotransmitter receptor desensitization?

Desensitization of neurotransmitter receptors can lead to reduced responsiveness of neurons to neurotransmitters, impacting synaptic plasticity and signaling pathways.

Define the relationship between neurotransmitter release and action potentials.

Action potentials stimulate the influx of calcium ions, which triggers the synaptic vesicles to fuse with the presynaptic membrane, releasing neurotransmitters.

What factors can influence neurotransmitter synthesis?

Neurotransmitter synthesis can be influenced by the availability of precursors, enzyme activity, genetic factors, and changes in neuronal activity.

Explain the concept of synaptic pruning and its importance.

Synaptic pruning is the process where excess synapses are eliminated, allowing the development of more efficient neural circuits and is crucial during brain maturation.

Describe the functions of endocannabinoids in the nervous system.

Endocannabinoids are lipid-based neurotransmitters that modulate synaptic transmission and plasticity, influencing pain regulation, mood, and memory.