• Ligand-Gated Ionotropic Chloride Channel
• Highest CNS expression of the 3 receptor types
• The target of benzodiazepines

Metabotropic Receptors

Baclofen is an agonist at this receptor

• Ligand-Gated Ionotropic Chloride Channel
• Has function in vision

• α
• β
• γ

• Binds allosterically to GABA-A receptor
• They bind to α subunits or to an area of the α subunit near the γ subunit
• They facilitate the process of channel opening but do not directly initiate the chloride current -- cannot activate the receptor by themselves

Therapeutic

• Reduces anxiety -- potentiation of GABAergic neurotransmission in the limbic system
• Sleep stages -- decreased latency period, increase total sleep time, less REM, less stages 3-4 more stage 2
• Anticonvulsant and muscle relaxant properties -- decrease seizure activity and muscle tone

ADRs

• Decrease alveolar ventilation at high doses -- decreased response to CO2 (resp. acidosis)
• Cardiovascular -- high doses decrease blood pressure -- reflex tachycardia

• Zolpidem
• Zaleplon
• Eszopiclone

Sedative

Antiseizure

BZDs

Zolpidem

Zaleplon

Eszopiclone

Anxiolytic

Myorelaxant

BZDs

• Melatonin Derivative
• High affinity for MT1 and MT2
• Good for reducing sleep latency but not for maintenance of sleep

• Both have hypnotic effect and decreased latency
• Non-BDZs are more selective and have less effect on sleep stages (REM, Stage 3-4)
• Non-BDZs have no daytime impairment
• Non-BDZs lack myorelexant and anxiolytic effects and have little to none anticonvulsant activity