Bicuculline-insensitive GABA binding to catfish neuronal membranes.

GABA receptor binding to mammalian neuronal membranes has been classified into at least 2 subtypes-GABA(A) and GABA(B) binding sites. In catfish brain GABA(A) receptor sites have previously been demonstrated. Evidence is now presented that under appropriate conditions which rule out GABA(A) receptor binding, [(3)H]GABA binds to membranes prepared from catfish brain.

Regulation of ?-aminobutyric acid synthesis in the vertebrate nervous system.

The regulation of glutamic decarboxylase (GAD) activity is undoubtedly the key to the control of the steady-state concentrations of 4-aminobutyric acid (GABA) in the central nervous system. Those factors that might influence GAD activity are reviewed. They include repression and induction of GAD synthesis; the interconversion of the holo- and apo-form of GAD; the availability of substrate and cofactor; the competitive inhibition of GAD by endogenous substances, including GABA; and the involvement of calcium ions in whole-cell preparations.

A relationship between synaptosomal GABA uptake and blood pressure in five inbred strains of mice.

Synaptosomal GABA uptake, sodium-dependent GABA binding to synaptic membranes and GABA receptor binding were measured in the cerebral cortex of five inbred strains of mice. These were the SWR/J, BALB/cJ, DBA/1J, C57BL/10J and C3HeB/FeJ strains. A highly significant negative correlation was found to exist between GABA uptake and blood pressure (r = ?0.

Action of analogues on ?-aminobutyric acid recognition sites in rat brain.

With a view to finding potential GABA-mimetics, the effects of a number of structural analogues of GABA were studied on three parameters associated with GABA neural transmission of rat brain. These were (1) the binding of [(3)H]GABA to its receptor, (2) the binding of [(3)H]GABA to its transporter (sodium-dependent binding), and (3) the activity of GABA aminotransferase. Thirteen of the 21 compounds tested competitively inhibited both the low and the high affinity GABA receptor binding components.