The central amygdala regulates sodium intake in sodium-depleted rats: role of 5-HT3 and 5-HT2C receptors.
In the present paper, we have evaluated the participation of 5-HT(3) and 5-HT(2C) receptors in the central amygdala (CeA) in the regulation of water and salt intake in sodium-depleted rats. m-CPBG-induced pharmacological activation of 5-HT(3) receptors located in the CeA resulted in a significant reduction in salt intake in sodium-depleted rats. This antinatriorexic effect of m-CPBG was reverted by pretreatment with the selective 5-HT(3) receptor antagonist ondansetron. The injection of ondansetron alone into the CeA had no effect on sodium-depleted and normonatremic rats. Conversely, pharmacological stimulation of 5-HT(2C) receptors located in the central amygdala by the selective 5-HT(2C) receptor agonist m-CPP failed to modify salt intake in sodium-depleted rats. Additionally, the administration of a selective 5-HT(2C) receptor blocker, SDZ SER 082, failed to modify salt intake in rats submitted to sodium depletion. These results lead to the conclusion that the pharmacological activation of 5-HT(3) receptors located within the CeA inhibits salt intake in sodium-depleted rats and that 5-HT(2C) receptors located within the CeA appear to be dissociated from the salt intake control mechanisms operating in the central amygdala.
Luz
C P
CP
Department of Biological Sciences, State University of Southwest Bahia 45200-000, Jequié, Bahia, Brazil.
Souza
A
A
Reis
R
R
Mineiro
P
P
Ferreira
H S
HS
Fregoneze
J B
JB
De Castro E Silva
E
E
D000679:Amygdala / Q000187:drug effects / Q000378:metabolism*; D000818:Animals; D001069:Appetite Regulation / Q000187:drug effects / Q000502:physiology*; D004326:Drinking / Q000187:drug effects / Q000502:physiology; D008297:Male; D008845:Microinjections; D051381:Rats; D017208:Rats, Wistar; D044405:Receptor, Serotonin, 5-HT2C / Q000187:drug effects / Q000378:metabolism*; D044406:Receptors, Serotonin, 5-HT3 / Q000187:drug effects / Q000378:metabolism*; D018490:Serotonin Agents / Q000494:pharmacology; D012982:Sodium, Dietary / Q000378:metabolism*
D044405:Receptor, Serotonin, 5-HT2C; D044406:Receptors, Serotonin, 5-HT3; D018490:Serotonin Agents; D012982:Sodium, Dietary