Question

You’ve got a problem in the action potential lab at “Organelles R Us.” Your lab partner has spiked the axon cultures with ouabain. Realizing that the depolarization and repolarization phases of the action potential are actually due to passive movement of ions through channel proteins, and that passive transport will eliminate concentration gradients, explain what happens (and why) to your cells’ ability to generate action potentials in the short term and in the long term.

Answer 1

Your lab partner has spiked the axon cultures with ouabain. Realizing that the depolarization and repolarization phases of the action potential are actually due to passive movement of ions through channel proteins, and that passive transport will eliminate concentration gradients, explain what happens (and why) to your cells’ ability to generate action potentials in the short term and in the long term.

Axon helps in conducting action potential from pre-synaptic neuron to the synaptic cleft of the post synaptic terminal of the cell. Special types of channels called voltage gated channels are responsible for generation of action potential which are embedded in the plama membrane of the cell. Oubain is the sodium/potassium pump inhibitor which causes sodium to remains inside the cell. Spiking the axon culture with oubain results in accumulation of sodium inside the cell and making it more positive. This triggers the export via sodium/calcium antiporter with simultaneous movement of calcium pumped into the cell. Action potential generated by voltage-gated sodium channels lasts maximum for 1ms. In the other hand, action potentials generated by voltage-gated calcium channels may sometimes last more than 100ms.