Cholecystokinin-induced variations in hypothalamic serotonergic system of the "cafeteria" rat.
Cholecystokinin octapeptide sulfate (CCK 8 S) appears to act via a serotonergic mechanism on several behavioral paradigms, including satiety. In the present study, CCK 8 S was found to induce slight nonsignificant serotonergic changes in hypothalamic nuclei of the normal rat. In the "cafeteria" rat, however, it increased both 5-HT and 5-HIAA levels in the ventromedial hypothalamus (VMH), 5-HT levels in the paraventricular nucleus (PVN) and decreased 5-HIAA levels in the dorsomedial hypothalamus (DMH). These data suggest that the primary site of action of CCK 8 S is in the median hypothalamus, contrasting with an absence of effect in the lateral hypothalamus (LH). The involvement of 5-HT in the effect of CCK 8 S is further suggested. However, the relationship between these neurochemical changes and CCK 8 S-induced satiety is not clear. Nonetheless, a special sensitivity to CCK 8 S of the obese "cafeteria" rat is evidenced, which contrasts with a reduced response of genetic obesity models.
Orosco
M
M
Laboratoire de Pharmacologie, CNRS URA 594, Faculté de Pharmacie, Châtenay-Malabry, France.
Gourch
A
A
Cohen
Y
Y
Jacquot
C
C
D000818:Animals; D005260:Female; D006897:Hydroxyindoleacetic Acid / Q000378:metabolism; D007031:Hypothalamus / Q000378:metabolism*; D009765:Obesity / Q000378:metabolism; D051381:Rats; D011919:Rats, Inbred Strains; D012527:Satiation / Q000187:drug effects*; D012701:Serotonin / Q000378:metabolism*; D012844:Sincalide / Q000494:pharmacology*
D012701:Serotonin; D006897:Hydroxyindoleacetic Acid; D012844:Sincalide