Difference Between Nicotinic and Muscarinic Receptors

Main Difference – Nicotinic vs Muscarinic Receptors

Nicotinic and muscarinic receptors are the two main types of cholinergic receptors.

They are integral membrane proteins activated by binding of the neurotransmitter acetylcholine. Although the same neurotransmitter binds to both receptors, each receptor has a different mechanism of action.

The key difference between nicotinic and muscarinic receptors is that when acetylcholine binds to the receptors , nicotinic receptors become sodium ion channels whereas muscarinic receptors phosphorylate various second messengers change .

 Nicotinic receptors are also called ionotropic acetylcholine receptors and muscarinic receptors are also called metabotropic acetylcholine receptors depending on their action .

Key areas covered

1. What are Nicotinic Receptors
– Definition, Facts, Mechanism of Action
2. What are Muscarinic Receptors
– Definition, Facts, Mechanism of Action
3. Similarities Between Nicotinic and Muscarinic Receptors are What
– Overview of Common Features
4. What is the Difference Between Nicotinic and Muscarinic Receptors
– Comparison of Key Differences

What are nicotinic receptors

  • Nicotinic receptors (nAhRs) are a group of cholinergic receptors that interact with nicotine in tobacco. They form pores through the cell membranes of postganglionic nerves. Since nicotinic receptors act as ligand-gated ion channels, they mediate the rapid transmission of nerve impulses at synapses.
  • Nicotinic receptors are permeable to cations such as sodium, potassium and calcium. The formation of ion channels upon agonist binding results in depolarization of neuronal cell membranes. This allows fast transmission of the signal.
  • The two nicotinic receptors are N1 and N2. N1 receptors are muscle-type receptors found in the neuromuscular junction. They are responsible for muscle contraction and relaxation. N2 receptors are neuron-type receptors found in synapses between neurons.
  •  They are involved in cognitive function, memory, learning, arousal, reward, motor control and analgesia. The structure of the nicotinic receptor is shown in Figure 1 .

 

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