Port-a-Patch application note: (2.7 MB)
Cells were kindly provided by Merck Millipore.
Gamma aminobutyric acid type A (GABAA) receptors are the most important inhibitory neurotransmitter receptors in the mammalian central nervous system (CNS). They are opened by GABA allowing the passage of chloride ions across the membrane. GABAA channels are modulated by a variety of different drugs including benzodiazepines, barbiturates, neuroactive steroids, anesthetics, and convulsants. The receptors are heteropentameric and depending on the subunit combination, they exhibit different electrophysiological and pharmacological properties. Six a-, three b-, three g-, one d-, one e-, one p-, one θ- and three r-subunits have been cloned, including splice variants of some of these subunits. Functional GABAA receptors typically assemble with two a, two b, and one g subunit, with alternating a and b subunits connected by a g subunit. GABAA receptors play a critical role in regulating excitability of the brain, anxiety, vigilance, as well as learning and memory. The a5 subunit is highly expressed in the hippocampus and olfactory bulb and expressed in low levels in other brain regions including the cortex, subiculum, hypothalamus, sympathetic preganglionic neurons, and amygdala. GABAA receptors containing the a5 subunit cluster at both extrasynaptic sites as well as synaptic sites thus contributing to tonic currents and synaptic GABA-ergic neurotransmission. a5 -containing receptors exhibit unique physiology and pharmacology and they are potential pharmacological targets for the treatment of neurodevelopmental disorders, depression, schizophrenia, and mild cognitive impairment. The Port-a-Patch with External Perfusion System was used to record a5b3g2 receptors expressed in HEK293 cells.