Effects of Polyamines on the Uptake of Neurotransmitters by Rat Brain Synaptosomes |
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Authors: | Che-Leung Law Patrick C L Wong Wang-Fun Fong |
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Institution: | Department of Biochemistry, Faculty of Medicine, University of Hong Kong, Hong Kong |
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Abstract: | Abstract: The influence of putrescine, spermidine, spermine, and some aliphatic α,ω-diamines on the uptake of neurotransmitters by rat forebrain synaptosomes was investigated. Choline uptake was most effectively inhibited by spermine (IC50= 0.22 m M ), less so by spermidine (IC50= 4.0 m M ), but not by putrescine (IC50 > 100 m M ). At 10 m M, 1,3-diaminopropane, cadaverine, and 1,8-diaminooctane all inhibited choline uptake by 50% or more. Spermine and spermidine inhibited the uptake of dopamine with IC50 values of 2.7 and 2.2 m M , respectively. Putrescine was only slightly inhibitory (IC50= 17.3 m M ) and the other diamines were inactive. The uptake of γ-aminobutyrate (GABA) was only slightly inhibited (15–40%) by the polyamines at 10 m M . With the exception of inhibition of glycine uptake by 1,8-diaminooctane (60%) and of glutamate uptake by cadaverine (35%) none of the polyamines, tested at 10 m M , affected the uptake of adenosine, glutamate, and glycine significantly. A possible modulatory role for polyamines in synaptic transmission through interaction by negatively charged groups of the synaptic membrane with the polycationic compounds is discussed. |
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Keywords: | Neurotransmitter uptake Polyamines Synaptosomes |
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