Plate and binding of ACh to nicotinic receptors

- The nicotinic ACh receptor is also a Na+ and K+ ion channel.

- Binding of ACh to a subunits of the receptor causes a conformational change that opens the central core of the channel and increases its conductance to Na+ and K+. These are examples of ligand-gated channels.

Table 1-2. Agents Affecting Neuromuscular Transmission

Example

Botulinus toxin

Curare

Action

Blocks release of ACh from presynaptic terminals

Competes with ACh for receptors on motor end plate

Effect on Neuromuscular Transmission

Total blockade

Decreases size of EPP; maximal doses produce paralysis of respiratory muscles and death

Hemicholinium Blocks reuptake of choline into presynaptic terminal

Neostigmine

Anticholinesterase

Prolongs and enhances action of ACh at muscle end plate

Depletes ACh stores from presynaptic terminal

ACh = acetylcholine; EPP = end plate potential.

Was this article helpful?

0 0
Anxiety and Depression 101

Anxiety and Depression 101

Everything you ever wanted to know about. We have been discussing depression and anxiety and how different information that is out on the market only seems to target one particular cure for these two common conditions that seem to walk hand in hand.

Get My Free Ebook


Post a comment