postsynaptic regulation

Question 1

What is postsynaptic regulation?

Answer 1

It’s the modulation of receptor response at the effector cell after neurotransmitter binding.

Question 2

What are the two types of postsynaptic regulation?

Answer 2

Modulation by previous activity and modulation by simultaneous events.

Question 3

What is up-regulation?

Answer 3

An increase in receptor number due to decreased activation or denervation.

Question 4

What causes up-regulation?

Answer 4

Low stimulation or denervation of the effector tissue.

Question 5

What is an example of up-regulation?

Answer 5

Denervation of skeletal muscle → proliferation of nicotinic receptors across the fiber.

Question 6

What is supersensitivity?

Answer 6

Exaggerated response due to receptor up-regulation after denervation or neurotransmitter depletion.

Question 7

What drug can cause pharmacologic supersensitivity?

Answer 7

Reserpine — depletes norepinephrine and leads to increased sensitivity of effector cells.

Question 8

What is down-regulation?

Answer 8

A decrease in receptor number due to prolonged or excessive stimulation.

Question 9

What causes down-regulation?

Answer 9

Chronic exposure to agonists or overstimulation of receptors.

Question 10

What is modulation by simultaneous events?

Answer 10

Postsynaptic response is altered by other transmitters acting on different receptors on the same cell.

Question 11

What is an example of simultaneous modulation?

Answer 11

Ganglionic transmission — multiple transmitters modulate postganglionic neuron response.

Question 12

Why is postsynaptic regulation important?

Answer 12

It fine-tunes autonomic output and prevents overstimulation or under-response.