A substance that does not act as agonist or antagonist but does affect the gamma-aminobutyric acid receptor-ionophore complex. GABA-A receptors appear to have at least three allosteric sites at which modulators act: a site at which benzodiazepines act by increasing the opening frequency of gamma-aminobutyric acid-activated chloride channels; a site at which barbiturates act to prolong the duration of channel opening; and a site at which some steroids may act.
Originally referring to an endogenous compound that is formed in specialized organ or group of cells and carried to another organ or group of cells, in the same organism, upon which it has a specific regulatory function, the term is now commonly used to include non-endogenous, semi-synthetic and fully synthetic analogues of such compounds.
A substance that does not act as agonist or antagonist but does affect the gamma-aminobutyric acid receptor-ionophore complex. GABA-A receptors appear to have at least three allosteric sites at which modulators act: a site at which benzodiazepines act by increasing the opening frequency of gamma-aminobutyric acid-activated chloride channels; a site at which barbiturates act to prolong the duration of channel opening; and a site at which some steroids may act.