Comparison of the Effects of Ethylenediamine Analogues and Γ‐aminobutyric Acid on Cortical and Pallidal Neurones

Abstract

1 The actions of ethylenediamine (EDA) and structurally related compounds were investigated by microiontophoresis in Wistar rats. 2 EDA inhibited, via a bicuculline-sensitive mechanism, the spontaneous firing rate of all cortical and pallidal cells tested. 3 The results with the analogues suggest that two amine groups are required for this neuronal depressant action whereas a carboxyl grouping is not. N-substitution reduces the depressant effect. The length of the molecule is also critical, more than 3 methylene components seriously reducing its effectiveness. A rigid analogue of EDA, piperazine, was also active. In addition the apparent transport numbers of EDA and y-aminobutyric acid (GABA) were calculated, showing a close similarity between the two. 4 The results are discussed with respect to the possibility that EDA may represent a new class of GABA-mimetics, or may indicate the existence of a novel diamine receptor mediating bicucullinesensitive inhibition in the rat CNS.

Actions of Gaba and Ethylenediamine on Ca1 Pyramidal Neurones of the Rat Hippocampus

“…Ethylenediamine (EDA) is thought to be a GABA agonist in some systems (Perkins & Stone, 1982). EDA may also release GABA and block the uptake of GABA (Forster, Lloyd, Morgan, Parker, Perkins & Stone, 1981).…”

ELECTROPHYSIOLOGICAL EFFECTS OF PIPERAZINE AND DIETHYLCARBAMAZINE ON Ascaris suum SOMATIC MUSCLE

“…In fact, Nistri & Constanti (1979) have suggested the existence of at least two separate types of GABA receptor in some invertebrates and some vertebrate preparations with piperazine as a selective agonist in invertebrates. However, piperazine does have a GABA mimetic action in some areas of the vertebrate central nervous system (Perkins & Stone, 1982).…”

A microiontophoretic study of the actions of the putative sleep factor, piperidine, in the rat brainstem

“…However it does inhibit [3H]-GABA uptake in rat brain synaptosomes (Nomura et al, 1978) and interestingly, piperazine, the diamino unsaturated analogue of piperidine, has been reported to be a good agonist for GABA receptors in rat cortex and pallidum (Perkins & Stone, 1982). Pipecolic acid, the immediate metabolic precursor of piperidine (Kase et al, 1967) also inhibits [jH]-GABA uptake (Nomura et al, 1978) and depresses the firing rate of hippocampal neurones when applied microiontophoretically (Kase et al, 1980).…”