Nicotinic vs muscarinic receptors

[thebillsfan]

Where can you find nicotinic receptors and where can you find muscarinic receptors in the body? What’s the advantage of one being a voltage-gated membrne channel (nicotinic) and another being a second-messenger system (muscarinic). In other words…why have two different kinds of acetylcholine receptors?

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[amberisma]

If I remember from Physiology correctly, nicotinic receptors are present on all of the postganglionic neurons as well as at the neuromuscular junction in skeletal muscles. They are always excitatory.

Muscarinic receptors are present in the autonomic nervous system, namely the parasympathetic. They can be either excitatory or inhibitory depending on the target tissue. I know on cardiac muscle they slow down the heart rate.

Basically the only reason I can think of why there are two different receptors because they have different agonists. I'm not sure if we learned why in my class. I'll have to look over my notes.

 

[thebillsfan]

but the agonists aren't different, are they? its Ach in both cases

 

[amberisma]

but the agonists aren't different, are they? its Ach in both cases

An Ach agonist for muscarinic receptors is muscarine.

For nicotinic receptors, the Ach agonist is nicotine.

Ach is the ligand for the two receptors.