Differential regulation of the brain and gut immunoreactive dynorphin by the serotonin system.
Administration of drugs such as fenfluramine, 20-40 mg/kg, and m-chlorophenylpiperazine (m-CPP), 2.5-5 mg/kg, which release serotonin or activate postsynaptic serotonin receptors, respectively, induced a dramatic decrease in the duodenal content of immunoreactive dynorphin (ir-DYN). The effect was antagonized by cyproheptadine, 1 mg/kg. Similarly, acute administration of the specific serotonin reuptake blockers fluvoxamine, 15 mg/kg, or femoxetine, 10 mg/kg, and 5-hydroxytryptophan (5-HTP), 40-160 mg/kg, evoked a marked decrease in the duodenal content of ir-DYN. A combined administration of fluvoxamine or femoxetine and 5-HTP failed to potentiate the effect of individual treatment. Only a higher dose of fenfluramine, 40 mg/kg, increased the ir-DYN content in the hypothalamus. These results suggest that the brain and gut ir-DYN is independently regulated by the serotonin system and that a serotonin mechanism might stimulate release of the gut dynorphin content.
Majeed
N H
NH
Lasoń
W
W
Przewłocka
B
B
Przewłocki
R
R
D006916:5-Hydroxytryptophan / Q000494:pharmacology; D000818:Animals; D001923:Brain Chemistry / Q000187:drug effects; D004399:Dynorphins / Q000032:analysis* / Q000276:immunology; D005277:Fenfluramine / Q000494:pharmacology; D007031:Hypothalamus / Q000032:analysis; D007422:Intestines / Q000032:analysis*; D008297:Male; D051381:Rats; D011919:Rats, Inbred Strains; D011985:Receptors, Serotonin / Q000187:drug effects; D012701:Serotonin / Q000502:physiology*
D011985:Receptors, Serotonin; D005277:Fenfluramine; D012701:Serotonin; D004399:Dynorphins; D006916:5-Hydroxytryptophan