Quisqualamine, a novel γ-aminobutyric acid (GABA)-related depressant amino acid

Abstract

A new substance, quisqualamine, the decarboxylated analogue of quisqualic acid, predictably depressed electrical activity of neurons of the frog and rat spinal cord in vitro and of the mouse spinal cord in vivo. In the in vitro preparations, the action of quisqualamine was associated with a prolonged depolarization of primary afferent terminals which was sensitive to blockade by picrotoxin and bicuculline and which was also depressed by strychnine. This suggests an interaction of quisqualamine with presynaptic receptors for both GABA and 8-alanine. Post-synaptic actions of quisqualamine, which were less marked than those at pre. synaptic sites, also appeared to be predominantly GABA-mimetic in vitro, though a sensitivity to the GABA-antagonist bicuculline could not be demonstrated in vivo.

High yielding synthesis of heterocyclic β-substituted alanine derivatives

“…Heterocyclic β-substituted alanines such as β-(pyrazol-1-yl)-alanine and quisqualic acid have been isolated from plant sources such as pressed juice of Citrullus vulgaris and from Quisqualis indica, respectively [1]; β-(pyrazol-1-yl)-alanine presents hypoglycemic properties [2], whilst quisqualic acid possesses potent neuroexcitatory activities [3,4]. Another heterocyclic β-substituted alanine, viz.…”

Neuroprotective Effects of N‐Alkyl‐1,2,4‐oxadiazolidine‐3,5‐diones and Their Corresponding Synthetic Intermediates N‐Alkylhydroxylamines and N‐1‐Alkyl‐3‐carbonyl‐1‐hydroxyureas against in vitro Cerebral Ischemia

“…[10] Quisqualic acid is an agonist for both metabotropic glutamate receptors coupled to phosphoinosotide hydrolysis [11] and the non-NMDA ionotropic a-amino-3-hydroxy-5-methylisoxazole-4-propionic acid (AMPA) receptor. [12] Compounds containing 1,2,4-oxadiazolidine-3,5-dione moieties were also found to be active as anti-hyperglycemic agents.…”