Types of Neutrotransmitter Receptor

Question 1

AChRs

Answer 1

ACh opens a nonselective ligand-gated cation channel which traffics K+, Na+, and also Cl-.

Due to their associated membrane potentials, the potential for Na+ being far greater than that of K+ at a resting negative membrane potential, Na+ influx is the dominating electrical force.

AChRs may be ionotropic (nicotinic) or metabotropic (muscarinic).
Activation of these receptors on motor endplates results in muscle contraction.

Question 2

Subtypes of ionotropic glutamate receptors

Answer 2

1. AMPA (glutamate-gated ion channel conducting Na+ and K+. Also require glycine as a co-agonistOpening causes depolarization in resting post-synaptic neurons).
2. Kainate
3. NMDA (glutamate-AND-glycine gated ion channel. Relies on a magnesium cation to block the entrance in the “closed” conformation. Conductance is greatly reduced when the post-synaptic neuron’s membrane potential is negative.

Question 3

GABA receptors

Answer 3

GABA-A receptors are metabotropic receptors structurally similar to nicotinic receptors which result in the opening of chloride channels. GABA-B receptors are metabotropic receptors that result in the opening of K+ channels. Both result in hyperpolarization by different mechanisms.

Question 4

GABA receptors

Answer 4

GABA-A receptors are metabotropic receptors structurally similar to nicotinic receptors which result in the opening of chloride channels. GABA-B receptors are metabotropic receptors that result in the opening of K+ channels. Both result in hyperpolarization by different mechanisms.