PET radioligands targeting the brain GABAA /benzodiazepine receptor complex

Ligand-gated ion channels are transmembrane proteins that play a vital role in intercellular communication and functions of the nervous system. They allow the influx of ions across the membrane once the neurotransmitter binds, allowing the subsequent transmission of electrical excitation across the neurons. Other ligand-gated ion channels, like the γ-aminobutyric acid (GABA) receptor, permit anions like chloride into the cells on the binding of the GABA molecule. Their entry into the cell...

γ-aminobutyric acid or GABA, plays a pivotal role as an inhibitory neurotransmitter in the brain. GABA pathway potentiators, also known as GABAergic drugs, are a class of pharmaceutical agents designed to enhance the functioning of the GABAergic system. These medications primarily treat epilepsy, a neurological disorder characterized by recurrent seizures.
The key GABA pathway potentiators used in epilepsy management are as follows.
Benzodiazepines are a well-known class of drugs used for...

G Protein-Coupled Receptors or GPCRs are membrane-bound receptors that transiently associate with heterotrimeric G proteins and induce an appropriate response to sensory stimuli such as light, odors, hormones, cytokines, or neurotransmitters.
GPCRs are also called heptahelical, 7TM, or serpentine receptors, and consist of seven (H1-H7) transmembrane alpha-helices that span the bilayer to form a cylindrical core. The transmembrane helices are connected by three extracellular loops and three...

Benzodiazepines are a class of anxiolytic drugs known for their rapid efficacy and high therapeutic-to-lethal dose ratio, but with a potential risk of drug dependence. These drugs are lipophilic, allowing for rapid absorption after oral administration, eventually reaching the central nervous system (CNS). Once in the CNS, benzodiazepines bind to the allosteric site of the GABAA receptor. This binding enhances the inhibitory effects of the neurotransmitter GABA. By doing so, they prevent...

Benzodiazepines have both sedative and hypnotic properties. They include compounds such as diazepam (Valium) and alprazolam (Xanax). Structurally, their cores are similar, consisting of the fusion of a benzene ring and a diazepine ring, but they share a common mechanism of action in the central nervous system (CNS).
Benzodiazepines work by enhancing the effects of the inhibitory neurotransmitter GABA. They bind to the GABAA receptor, increasing its affinity for GABA, which opens chloride...

G-protein coupled receptors are ligand binding receptors that indirectly affect changes in the cell. The actual receptor is a single polypeptide that transverses the cell membrane seven times creating intracellular and extracellular loops. The extracellular loops create a ligand specific pocket which binds to neurotransmitters or hormones. The intracellular loops holds onto the G-protein.