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THE EFFECT OF PHOSPHOLIPASES ON THE ACTIVE UPTAKE OF NOREPINEPHRINE BY SYNAPTOSOMES ISOLATED FROM THE CEREBRAL CORTEX OF GUINEA PIG 1
Author(s) -
Sun A. Y.
Publication year - 1974
Publication title -
journal of neurochemistry
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.75
H-Index - 229
eISSN - 1471-4159
pISSN - 0022-3042
DOI - 10.1111/j.1471-4159.1974.tb06893.x
Subject(s) - phospholipase , norepinephrine , synaptosome , phospholipase c , phospholipid , phospholipase a , phospholipase a2 , chemistry , guinea pig , biochemistry , cerebral cortex , enzyme , biology , endocrinology , medicine , membrane , dopamine
—Phospholipase A (EC 3.1.1.4) and phospholipase C (EC 3.1.4.3) were used for studying the role of phospholipid of synaptosomal membrane on norepinephrine uptake activity. Synaptosomes were isolated from cerebral cortex of guinea pigs and treated with phospholipase A or phospholipase C before the uptake experiments. Treatment of synaptosomes with phospholipase A has resulted in severe inhibition of norepinephrine‐uptake. Under similar conditions, the activity of synaptosomal (Na + K)‐ATPase (EC 3.6.1.4) was also inhibited by phospholipase A treatment whereas the activity of synaptosomal acetylcholinesterase (EC 3.1.1.8) was not affected. On the other hand, the norepinephrine‐uptake was not influenced by phospholipase C treatment. The inhibition of norepinephrine‐uptake after phospholipase A treatment may be due to the liberation of lyso‐components of phospholipids since a low concentration of lysolecithin as well as other detergents (deoxycholate and sodium dodecyl sulphate) also inhibit the uptake activity. However, electron microscopic examination indicated that the synaptosomal particles still maintain their morphological features after phospholipase A treatment. It is possible that the active uptake of norepinephrine depends upon the fine arrangement of phospholipids present at the active sites of the synaptosomal membrane.