Which types of ion channels are found on the nerve cell membranes?

Voltage gated channels

Ligand gated channels

Name 3 differences between voltage-gated and ligand-gated ion channels.

• Voltage gated works by reaction to changes in membrane potential whereas ligand gated works by ligand binding to ion channel that has affinity for it.
• Voltage gated ion channels initiates fast all or nothing action potential which propagates down neuron where ligand gated consists of many subunits and when stimulated a brief opening of the channel which causes a fast synaptic transmission.
• Voltage gated channels are ion specific whereas ligand gated channels are not

Compare ionotropic and metabotropic receptors.

Ionotropic channels or ligand gated channels consists of multiple subunits and when a neurotransmitter binds to it directly opens the channels. They are directly responsible for fast synaptic transmissions whereas metabotropic receptors are G protein coupled and when binding occurs on receptor it does not result in direct opening of gate but  the initiation of a pathway that gives rise to a secondary messenger .

Classify the CNS receptors into ionotropic and metabotropic and know the transduction mechanism of each receptor.

Ionotropic receptors: nicotinic, Cl, Na, EAA(glutamate), GABAa

Metabotropic receptors are divided into 2 groups

• Adenylyl cyclase system

Neurotransmitters can bind positively (R+) to adenylyl cyclase 1&2 and dopamine which causes increased AMP formation

Negative binding (R-) means it is negatively bound therefore decrease in AMP formation

• Phospholipase system

All receptors are positively bound meaning increased enzyme activity IP3 and DAG

Explain the difference between an EPSP and an IPSP and give examples of each

EPSP- excitatory post synaptic potential

This happens due to the opening of sodium and calcium channels when a neurotransmitter binds, this causes increased permeability to cations that causes depolarization and in turn causes threshold to be reached and an action potential forms.

Examples of receptors that will bring this to effect: 5-HT3, Nicotinic, EAA, BD

IPSP- inhibitory post synaptic potential

This happens when an action potential is stopped by hyperpolarization of the post synaptic membrane which is achieved by potassium and chloride channels opening when a neurotransmitter GABAa binds

What is the role of calcium in the development of a synaptic potential?

Ca is very important as it stimulates the release of neurotransmitters from the axon terminal as the action potential reaches membrane calcium flows into the synaptic vessel stimulating the release of neurotransmitters.