Central 5-HT(4) receptors and drinking behavior.
The aim of the present study was to investigate the effect of acute third ventricle injections of two different 5-HT(4) receptor antagonists, GR 113808 and SB 204070, on water intake in different situations. Injections of 80 nmol/rat of both GR 113808 and SB 204070 were unable to modify water intake in normohydrated rats. Pretreatment with GR 113808 (40 and 80 nmol/rat) and SB 204070 (80 and 160 nmol/rat) blunted water intake after third ventricle injections of angiotensin II (9.6 pmol/rat) compared to saline-pretreated controls. Pretreatment with 80 nmol/rat of both antagonists potentiated drinking induced by third ventricle injections of carbachol (11.0 nmol/rat) compared to saline-pretreated control. In all doses employed, none of the compounds was able to modify water intake in dehydrated rats. A separate control test using one-bottle taste aversion paradigm indicated that the reduction in water intake observed in some of the present experiments could not be attributed to a drug-induced malaise. It is suggested that central 5-HT(4) receptors exert a dualistic role on the control of water intake potentiating angiotensin II-induced drinking and inhibiting thirst induced by central cholinergic activation
Castro
L
L
Department of Physiology, Health Sciences Institute, Federal University of Bahia, 40110-100 Salvador, Bahia, Brazil.
De Castro-E-Silva
E
E
Lima
A K
AK
Souza
F S
FS
Maldonado
I
I
Macêdo
D F
DF
Ferreira
M G
MG
Santamaria
G F
GF
Bandeira
I P
IP
Amor
A L
AL
Carvalho
F L
FL
Rocha
M A
MA
Oliveira
I R
IR
Fregoneze
J B
JB
D000818:Animals; D004146:Dioxanes / Q000008:administration & dosage; D004326:Drinking / Q000187:drug effects / Q000502:physiology; D004327:Drinking Behavior / Q000187:drug effects / Q000502:physiology*; D007211:Indoles / Q000008:administration & dosage; D007276:Injections, Intraventricular; D008297:Male; D010880:Piperidines / Q000008:administration & dosage; D051381:Rats; D017208:Rats, Wistar; D011985:Receptors, Serotonin / Q000502:physiology*; D044422:Receptors, Serotonin, 5-HT4; D012702:Serotonin Antagonists / Q000008:administration & dosage; D013449:Sulfonamides / Q000008:administration & dosage; D013894:Thirst / Q000187:drug effects / Q000502:physiology; D014868:Water Deprivation / Q000502:physiology
D004146:Dioxanes; D007211:Indoles; D010880:Piperidines; D011985:Receptors, Serotonin; D012702:Serotonin Antagonists; D013449:Sulfonamides; C084858:SB 204070A; D044422:Receptors, Serotonin, 5-HT4; C082871:GR 113808