High concentrations of calmodulin antagonists inhibit accumulation and binding activities of [(3)H]glutamate in rat brain.
Sodium- and energy-dependent accumulation of [(3)H]l-glutamic acid (Glu) into rat cerebral cortical slices was inhibited by relatively high concentrations (40-100 ?M) of calmodulin antagonists, such as N-(6-aminohexyl)-1-naphthalenesulfonamide and N-(6-aminohexyl)-5-chloro-1-naphthalenesulfonamide, in concentration-dependent and noncompetitive manners. The latter antagonist not only diminished the basal binding activity of [(3)H]Glu in synaptic membranes of the rat brain, but also eliminated the activities found in the presence of Cl(?) and Cl(?)/Ca(2+) ions. However, N- methyl- d -aspartate-sensitive [(3)H]Glu binding was not affected by these antagonists. These results suggest the possible involvement of the calmodulin system in glutamatergic neurotransmission in the brain.
Yoneda
Y
Y
Department of Pharmacology, Setsunan University, Hirakata, Osaka 573-01, Japan.
Ogita
K
K
Yamada
K
K
Kouda
T
T
Ohgaki
T
T
Uchida
S
S
Meguri
H
H