Final answer:
The ligand-gated ion channels that are inhibitory and concentrate at inhibitory synapses in the brain are GABA-A receptors and glycine receptors. GABA-A receptors are ionotropic chloride channels that decrease the cell's excitability, while glycine receptors also act as ionotropic chloride channels, leading to a decrease in neuronal excitability.
Step-by-step explanation:
The ligand-gated ion channels that are inhibitory and concentrate at inhibitory synapses in the brain are GABA-A receptors, also known as gamma-aminobutyric acid receptors. GABA-A receptors are ionotropic chloride channels that allow the influx of chloride ions, hyperpolarizing the membrane and decreasing the excitability of the cell. The activation of GABA-A receptors by GABA causes an inhibitory effect on the postsynaptic neuron.
Another inhibitory ligand-gated ion channel that concentrates at inhibitory synapses in the brain is the glycine receptor. Glycine receptors also act as ionotropic chloride channels, allowing chloride ions to enter the cell and hyperpolarizing the membrane, leading to a decrease in neuronal excitability.