Dopaminergic agents affected neuronal transmission of cholecystokinin in the rat brain.
In order to study the interaction between cholecystokinin (CCK) and dopamine (DA), we prepared an anti-CCK-8 antibody with low cross reactivity, and observed effects of administered various dopaminergic agents on CCK-immunoreactivity (CCK-IR) in discrete brain regions of rats. CCK-8 IR (boiling water extraction) and CCK-33 IR (acetic acid extraction) were also measured in the same sample. A single administration of haloperidol decreased the CCK-8 IR in the corpus striatum and that of racemic sulpiride significantly decreased the CCK-8 IR in the frontal cortex and the limbic system. In contrast, a single administration of apomorphine or methamphetamine increased the CCK-8 IR in the same regions. These findings suggest that an acute response of the CCK system to administered dopaminergic agents may be due to a change in the rate of release of CCK-8, but not to a change in its synthesis in areas in which DA neurons originating in the midbrain innervate. After chronic administration of racemic sulpiride or methaphetamine, CCK-8 IR in various brain regions exhibited a tendency close to that of control.
Fukamauchi
F
F
Department of Neuropsychiatry, Faculty of Medicine, Tokyo Medical and Dental University, Japan.
Yoshikawa
T
T
Kaneno
S
S
Shibuya
H
H
Takahashi
R
R
D000818:Animals; D001921:Brain / Q000187:drug effects* / Q000378:metabolism; D006220:Haloperidol / Q000494:pharmacology; D007106:Immune Sera / Q000276:immunology; D008297:Male; D008694:Methamphetamine / Q000494:pharmacology; D011863:Radioimmunoassay; D051381:Rats; D011919:Rats, Inbred Strains; D011954:Receptors, Dopamine / Q000187:drug effects*; D012844:Sincalide / Q000032:analysis / Q000276:immunology / Q000378:metabolism*; D009435:Synaptic Transmission / Q000187:drug effects*
D007106:Immune Sera; D011954:Receptors, Dopamine; D008694:Methamphetamine; D006220:Haloperidol; D012844:Sincalide