title: The activity of cis and trans -2- (aminomethyl) cyclopropane carboxylic acids on GABA - related mechanisms in the central nervous system of Limulus and Periplanata and of mammals.
abstract: Some pharmacological actions of (+/-) - cis - and (+/-) - trans -2-(aminomethyl) cyclopropane carboxylic acids, conformationally restricted analogues of GABA, are described. The trans isomer (TAMP) was 17 and 4.5 times less active than GABA in hyperpolarising central neurones of Limulus and Periplanata and 10.8 times less active in displacing [3H]-muscimol from rat brain membranes. The cis isomer (CAMP) was ineffective on Limulus neurones at 35 mumoles, 650 times less active on Periplanata neurones and only weakly displaced [3H]-muscimol at 100 microM. Neither isomer inhibited synaptosomal uptake of [3H]-GABA at 100 microM. These data suggest that the invertebrate receptors studied respond to GABA in an extended conformation.
mesh_terms: D000818:Animals; D001667:Binding, Competitive; D002490:Central Nervous System / Q000187:drug effects*; D003058:Cockroaches / Q000502:physiology*; D003521:Cyclopropanes / Q000494:pharmacology*; D006737:Horseshoe Crabs / Q000502:physiology*; D066298:In Vitro Techniques; D008968:Molecular Conformation; D009118:Muscimol / Q000378:metabolism; D009474:Neurons / Q000187:drug effects; D051381:Rats; D013045:Species Specificity; D013574:Synaptosomes / Q000378:metabolism; D005680:gamma-Aminobutyric Acid / Q000031:analogs & derivatives* / Q000494:pharmacology / Q000502:physiology*
chemical_list: D003521:Cyclopropanes; D009118:Muscimol; D005680:gamma-Aminobutyric Acid