Nicotinic cholinergic receptors allow simultaneous passage o

Nicotinic cholinergic receptors allow simultaneous passage of Na+ and K+. What neurotransmitter do these receptors bind? Explain how stimulation of these channels leads to excitation.

Solution

Nicotinic cholinergic receptors bind to both acetylcholine and nicotine. Nicoitinic receptors are ligand gated channels. Nicotinic acetylcholine receptors at peripheral synapses mediate rapid and effective excitatory synaptic transmission Binding of ligand to this receptor causes conformational change by rearrangement of hydrogen bonds around the aspartate residue, polar groups in the chain and water molecule. Binding of ligand opens the channels and allows the influx of sodium ions . This entry of Na ions into the cells causes depolarisation which leads to the excitation of the cell. Two types nicotinic receptors are found , N1 receptor and N2 receptor. N1 receptor - They are found only in neuromuscular junction. N2 receptor -They are found both at cholinergic and adrenergic ganglia, but not at the target tissues (e.g, heart, bladder, etc). These receptors are also present in the CNS and adrenal medulla.