Effect of a cholecystokinin preparation on brain monoamines in the rat

In order to elucidate the central action mechanism of cholecystokinin (CCK), effects of this peptide on norepinephrine, dopamine and serotonin contents in the brain were observed in saline control, alpha-methyl-p-tyrosine-, L-DOPA- and pargyline-pretreated rats. Intraperitoneal injection of CCK in a dose of 40 U/kg did not produce any significant changes in the monoamine contents. However, since a tendency to increase in norepinephrine turnover rate after CCK injection was noticed, the possibility that brain monoamines are involved in the central action of CCK could not be excluded.