Satiety function of neurons containing a CCK-like substance in the dorsal parabrachial nucleus.
Glutaryl-CCK-8 (Glt-CCK-8, 16-160 pmol) suppressed food intake dose dependently when injected into the ventromedial hypothalamus (VMH) bilaterally, but not when injected unilaterally. In contrast, CCK-8 (160 and 320 pmol) did not suppress food intake when injected into the VMH bilaterally. When injected intraperitoneally, Glt-CCK-8 significantly decreased food intake at a dose of 320 pmol, though not at a dose of 160 pmol, whereas CCK-8 significantly reduced food intake even at a dose of 160 pmol. Pretreatment with proglumide, an antagonist of CCK-8, counteracted the effect on food intake of CCK-8 injected intraperitoneally, but did not influence that of Glt-CCK-8 injected either into the VMH or intraperitoneally. However, CCK-8 (800 pmol) prevented the satiety action of Glt-CCK-8 when injected into the VMH before the latter. Since a large dose of CCK-8 injected into the VMH was reported to suppress food intake, these findings suggest that, among the receptors for the satiety action of CCK, intracranial receptor has lower affinity for CCK-8 than for Glt-CCK-8 and peripheral receptor has higher affinity for CCK-8 than for Glt-CCK-8. Furthermore, bilateral lesions of the lateral part of the dorsal parabrachial nucleus (LPBD), from which the neurons containing a CCK-8-like substance extend fibers to the VMH, enhanced the satiety action of Glt-CCK-8 injected into the VMH. These results support the idea that these neurons which project to the VMH are involved in the satiety action.
Takaki
A
A
Division of Protein Metabolism, Osaka University, Japan.
Nagai
K
K
Takaki
S
S
Yanaihara
N
N
Nakagawa
H
H
D000818:Animals; D001931:Brain Mapping; D002766:Cholecystokinin / Q000502:physiology*; D005247:Feeding Behavior / Q000187:drug effects / Q000502:physiology*; D006815:Hunger / Q000187:drug effects / Q000502:physiology; D008297:Male; D009042:Motivation; D009434:Neural Pathways / Q000187:drug effects / Q000502:physiology; D009474:Neurons / Q000187:drug effects / Q000502:physiology; D011149:Pons / Q000502:physiology*; D051381:Rats; D011919:Rats, Inbred Strains; D012528:Satiety Response / Q000187:drug effects / Q000502:physiology*; D012844:Sincalide / Q000494:pharmacology; D014697:Ventromedial Hypothalamic Nucleus / Q000187:drug effects / Q000502:physiology
D002766:Cholecystokinin; D012844:Sincalide