Transport Proteins?

Question

Explain the role of transport proteins in the transmission of an action potential up to and across a synapse. Explain how the neurotransmitter is released and detected to continue the action potential in the postsynaptic cell.

Answer 1

Transport proteins are all important in the transmission of a nervous impulse along a nerve axon and across the synapse.

Are you considering the ion channels as transport proteins also?

Sodium/Potassium ATPase pump generates the resting membrane potential by pumping 3Na+ out of the cell and 2K+ into the cell. This establishes the Resting Potential

Voltage Gated Sodium Channels respond to a stimulus by allowing an influx of Na+ changing the resting potential and making it more positive.

Voltage Gated Potassium Channels open when the peak level is reached and lower the membrane potential again as K+ leaks out.

A similar process occurs at the synapse with the triggering of voltage gated Calcium Channels which will set in motion the process of exocytosis of the neurotransmitters. The neurotransmitters cross the synaptic cleft and then bind to postsynaptic receptors (themselves proteins and ion channels) and may be excitatory (reducing the membrane potential) or inhibitory (increasing the negativity of the membrane potential and making it harder to get to the stimulation point for the Voltage Gated Na Channels to open). In the case of excitatory neurotransmitters and receptors binding, then when the decrease in membrane potential is sufficient to trigger the Na Channels, they open and continue the action potential propagation within this second neuron.