Interaction of serotonin and cholecystokinin in the lateral parabrachial nucleus to control sodium intake.
Serotonin [5-hydroxytryptamine (5-HT)] and CCK injected into the lateral parabrachial nucleus (LPBN) inhibit NaCl and water intake. In this study, we investigated interactions between 5-HT and CCK into the LPBN to control water and NaCl intake. Male Holtzman rats with cannulas implanted bilaterally in the LPBN were treated with furosemide + captopril to induce water and NaCl intake. Bilateral LPBN injections of high doses of the 5-HT antagonist methysergide (4 microg) or the CCK antagonist proglumide (50 microg), alone or combined, produced similar increases in water and 1.8% NaCl intake. Low doses of methysergide (0.5 microg) + proglumide (20 microg) produced greater increases in NaCl intake than when they were injected alone. The 5-HT(2a/2c) agonist 2,5-dimetoxy-4-iodoamphetamine hydrobromide (DOI; 5 microg) into the LPBN reduced water and NaCl intake. After proglumide (50 microg) + DOI treatment, the intake was not different from vehicle treatment. CCK-8 (1 microg) alone produced no effect. CCK-8 combined with methysergide (4 microg) reduced the effect of methysergide on NaCl intake. The data suggest that functional interactions between 5-HT and CCK in the LPBN may be important for exerting inhibitory control of NaCl intake.
Fratucci De Gobbi
J I
JI
Department of Physiology and Pathology, School of Dentistry, Paulista State University (UNESP), 14801 - 903 Araraquara, São Paulo, Brazil.
De Luca
L A
LA
Johnson
A K
AK
Menani
J V
JV
D000662:Amphetamines / Q000494:pharmacology; D000818:Animals; D001066:Appetite / Q000187:drug effects / Q000502:physiology*; D004347:Drug Interactions; D006706:Homeostasis; D020646:Intralaminar Thalamic Nuclei / Q000187:drug effects / Q000502:physiology*; D008297:Male; D008784:Methysergide / Q000008:administration & dosage / Q000494:pharmacology; D008845:Microinjections; D008959:Models, Neurological; D009474:Neurons / Q000187:drug effects / Q000502:physiology; D011377:Proglumide / Q000494:pharmacology; D051381:Rats; D017207:Rats, Sprague-Dawley; D012701:Serotonin / Q000008:administration & dosage / Q000494:pharmacology*; D017366:Serotonin Receptor Agonists / Q000494:pharmacology; D012844:Sincalide / Q000008:administration & dosage / Q000031:analogs & derivatives* / Q000494:pharmacology*; D012982:Sodium, Dietary
C090019:8-sulfocholecystokinin octapeptide; D000662:Amphetamines; D017366:Serotonin Receptor Agonists; D012982:Sodium, Dietary; D012701:Serotonin; D011377:Proglumide; D012844:Sincalide; C015952:4-iodo-2,5-dimethoxyphenylisopropylamine; D008784:Methysergide