Question

The one-way flow of information between presynaptic and postsynaptic cells is characteristic of most kinds of neuron interactions. A notable exception to this rule is the:
A. Neuromuscular junction
B. Nicotinic receptor system of vertebrate neurons
C. Motor end plate
D. Gap junction

Answer 1

Hint:
The messages from the central nervous system are brought by the motor neuron. When a motor neuron reaches an organ it releases a neurotransmitter into the synaptic cleft. These neurotransmitters bind with receptors present in the postsynaptic cell and release the nerve impulse into the cell which generates the action potential in the postsynaptic cell.

Complete answer:
The space between two adjacent neurons is called the synapse or a neuromuscular junction. Gap junctions are the electrical synapses that physically connect the neurons by the membrane protein due to which the electrical signals can travel in either direction. These gap junctions provide direct communication between the cells. These can be found in nerve cells, hepatocytes, etc. The nicotinic receptors are present on the postsynaptic cell and the acetylcholine (a neurotransmitter) binds with it to enhance the firing rate of a subset of hypocretin neurons in the mouse hypothalamus. Here, the typical flow of nerve impulses from the presynaptic cell to the postsynaptic cell is observed.
Thus, the correct answer is:- Gap junctions

Option ‘D’ is correct

Note:
One gap junction is composed of two protein hexamers. These gap junctions are similar to the plasmodesmata that join the plant cells. Gap junctions are not found in the skeletal muscles of a fully developed adult and in mobile cells such as sperms or erythrocytes. As we know gap junctions perform the function of providing better communication between the cells, this communication can be disturbed by adding anti-connexin antibodies into the embryonic cell.