Effect of succinyl cholecystokinin heptapeptide on synaptosomal 45Ca uptake of mouse hippocampus
Abstract
AIM: To study the effect of a new peptide, succinyl cholecystokinin heptapeptide (SCH), on the uptake of 45Ca by synaptosomes from mouse hippocampus, and compare it with that of sincalide.
METHODS: Protein concentration was determined by the dye method. 45Ca uptake was determined by adding 45CaCl2 into synaptosome suspending solution. Samples were incubated and terminated by filtration through glass microfiber filters and finally counted in a Beckman LS 9800 liquid scintillation spectrometer.
RESULTS: SCH 0.125 - 2 mumol.L(-1) dose-dependently depressed synaptosomal 45Ca uptake, and the depressive extent was similar to that of sincalide. The suppressive effect induced by either SCH or sincalide on synaptosomal 45Ca uptake was antagonized by proglumide, which itself did not affect 45Ca uptake of synaptosomes. The inhibition of synaptosomal 45Ca uptake induced by SCH or sincalide was blocked by beta-endorphin.
CONCLUSION: The replacement of the N-terminal aspartic acid residue of sincalide does not influence its effect on 45Ca uptake of hippocampal synaptosomes.
Keywords:
METHODS: Protein concentration was determined by the dye method. 45Ca uptake was determined by adding 45CaCl2 into synaptosome suspending solution. Samples were incubated and terminated by filtration through glass microfiber filters and finally counted in a Beckman LS 9800 liquid scintillation spectrometer.
RESULTS: SCH 0.125 - 2 mumol.L(-1) dose-dependently depressed synaptosomal 45Ca uptake, and the depressive extent was similar to that of sincalide. The suppressive effect induced by either SCH or sincalide on synaptosomal 45Ca uptake was antagonized by proglumide, which itself did not affect 45Ca uptake of synaptosomes. The inhibition of synaptosomal 45Ca uptake induced by SCH or sincalide was blocked by beta-endorphin.
CONCLUSION: The replacement of the N-terminal aspartic acid residue of sincalide does not influence its effect on 45Ca uptake of hippocampal synaptosomes.