Central administration of zinc reduces salt intake in rats.
The aim of the present study was to investigate the effect of third ventricle injections of zinc on salt intake in rats in the three different experimental models where sodium appetite is increased: fluid deprivation, central angiotensinergic stimulation and sodium depletion. Adult Wistar male rats received third ventricle injections of Zn(Ac)2 in three different doses (0.03, 0.3 and 3.0 nmol/rat). Central angiotensinergic stimulation was achieved by third ventricle injections of angiotensin II in the dose of 25 ng/rat 30 min before central zinc administration. As expected, fluid deprivation, central angiotensinergic stimulation and sodium depletion significantly increased sodium appetite. Water intake was also enhanced after fluid deprivation and central angiotensinergic stimulation. After sodium depletion, no increase in water intake was observed. Third ventricle injections of zinc inhibited salt intake in all three experimental models studied. Water intake was also inhibited by central zinc administration after fluid deprivation and central angiotensinergic stimulation. Conversely, third ventricle injections of zinc were unable to modify food intake or body temperature. It is suggested that zinc, acting on central structures related to the control of body fluid homeostasis, inhibits the drive for salt intake that is normally observed during fluid deprivation, central angiotensinergic stimulation and sodium depletion.
De Castro-e-Silva
Emilio
E
Department of Physiology, Health Sciences Institute, Federal University of Bahia, 40110-100 Salvador, Bahia, Brazil. emilio@svn.com.br
Ferreira
Hilda Silva
HS
Magrani
Janeide
J
Santamaria
Guillermo Fernandez
GF
Fregoneze
Josmara Bartolomei
JB
D000804:Angiotensin II / Q000008:administration & dosage / Q000494:pharmacology; D000818:Animals; D004326:Drinking / Q000187:drug effects; D004435:Eating / Q000187:drug effects; D005508:Food Deprivation / Q000502:physiology; D005518:Food Preferences / Q000187:drug effects*; D007276:Injections, Intraventricular; D008297:Male; D008845:Microinjections; D051381:Rats; D017208:Rats, Wistar; D017673:Sodium Chloride, Dietary / Q000008:administration & dosage; D013268:Stimulation, Chemical; D014868:Water Deprivation / Q000502:physiology; D015032:Zinc / Q000008:administration & dosage / Q000494:pharmacology*
D017673:Sodium Chloride, Dietary; D000804:Angiotensin II; D015032:Zinc