Uptake and Calcium‐Dependent Release of Ethylenediamine (1,2‐Diaminoethane) by Rat Brain Slices

Abstract

The uptake of [14C]ethylenediamine into slices of rat brain and its subsequent evoked release have been studied. An active uptake process was demonstrated by comparing uptake at 37 and 4 degrees C. This uptake showed a Km of 1.36 mM, was partly sodium-dependent and was reduced by nipecotic acid. Release could be readily evoked by 30 mM potassium, and by electrical stimulation, the release in both cases being calcium-dependent. In view of these findings and the reported interactions of ethylenediamine with gamma-aminobutyric acid-related mechanisms, it might be of interest to determine whether this simple diamine occurs endogenously in the mammalian brain.

Structure‐activity studies on the potentiation of benzodiazepine receptor binding by ethylenediamine analogues and derivatives

“…EDA can also release [3H]-yaminobutyric acid (GABA) and inhibit [3H]-GABA uptake in rat brain slices (Forster et al, 1981;Lloyd, Perkins, Gaitonde & Stone, 1982a;Lloyd, Perkins & Stone, 1982b), depolarize the superior cervical ganglion with a pharmacological profile of action similar to GABA (Bowery, Hill, Hudson, Perkins & Stone, 1982). Taken collectively the evidence strongly suggests that EDA acts upon GABA receptors .…”

“…Ethylenediamine (EDA) causes a marked depression of neuronal activity when applied iontophoretically to central neurones (Anderson, Haas & Hosli, 1973;Phillis, 1977;Perkins & Stone, 1980; Perkins, Bowery, Hill & Stone, 1981) and this action can be antagonized by bicuculline (Forster, Lloyd, Morgan, Parker, Perkins & Stone, 1981;. EDA can also release [3H]-yaminobutyric acid (GABA) and inhibit [3H]-GABA uptake in rat brain slices (Forster et al, 1981;Lloyd, Perkins, Gaitonde & Stone, 1982a;Lloyd, Perkins & Stone, 1982b), depolarize the superior cervical ganglion with a pharmacological profile of action similar to GABA and displace [3H]-GABA, [3H]-muscimol, and [3H]-baclofen binding to rat synaptic membrane (Bowery, Hill, Hudson, Perkins & Stone, 1982). Taken collectively the evidence strongly suggests that EDA acts upon GABA receptors .…”

Anticonvulsant Actions of the Putative Γ‐aminobutyric Acid (Gaba)‐mimetic, Ethylenediamine

“…EDA can also be actively taken up by rat brain slices and released by potassium in a calcium-dependent manner (Lloyd, Perkins, Gaitonde & Stone, 1982a) and has been reported to be useful as a specific releasing agent of GABA in rat brain slices (Lloyd, Perkins & Stone, 1982b). EDA thus appears to activate GABA-ergic mechanisms by both direct and indirect means.…”