Effect of electrolytic lesion of the dorsal raphe nucleus on water intake and sodium appetite
The present study determined the effect of an electrolytic lesion of the dorsal raphe nucleus (DRN) on water intake and sodium appetite. Male Wistar rats weighing 290-320 g with a lesion of the DRN (L-DRN), performed two days before experiments and confirmed by histology at the end of the experiment...
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Associação Brasileira de Divulgação Científica
2003-12-01
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doaj-2359ff0a3f9345fe80a8789be827d2502020-11-24T23:30:12ZengAssociação Brasileira de Divulgação CientíficaBrazilian Journal of Medical and Biological Research0100-879X1414-431X2003-12-0136121709171610.1590/S0100-879X2003001200013Effect of electrolytic lesion of the dorsal raphe nucleus on water intake and sodium appetiteE.L. OlivaresR.H. Costa-e-SousaH.R. Cavalcante-LimaH.R.C. LimaP.L. Cedraz-MercezL.C. ReisThe present study determined the effect of an electrolytic lesion of the dorsal raphe nucleus (DRN) on water intake and sodium appetite. Male Wistar rats weighing 290-320 g with a lesion of the DRN (L-DRN), performed two days before experiments and confirmed by histology at the end of the experiments, presented increased sensitivity to the dehydration induced by fluid deprivation. The cumulative water intake of L-DRN rats reached 23.3 ± 1.9 ml (a 79% increase, N = 9) while sham-lesioned rats (SL-DRN) did not exceed 13.0 ± 1.0 ml (N = 11, P < 0.0001) after 5 h. The L-DRN rats treated with isoproterenol (300 µg kg-1 ml-1, sc) exhibited an increase in water intake that persisted throughout the experimental period (L-DRN, 15.7 ± 1.47 ml, N = 9 vs SL-DRN, 9.3 ± 1.8 ml, N = 11, P < 0.05). The L-DRN rats also showed an increased spontaneous sodium appetite during the entire period of assessment. The intake of 0.3 M NaCl after 12, 24, 36 and 72 h by the L-DRN rats was always higher than 20.2 ± 4.45 ml (N = 10), while the intake by SL-DRN was always lower than 2.45 ± 0.86 ml (N = 10, P < 0.00001). Sodium- and water-depleted L-DRN rats also exhibited an increased sodium appetite (13.9 ± 2.0 ml, N = 11) compared to SL-DRN (4.6 ± 0.64 ml, N = 11) after 120 min of observation (P < 0.02). The sodium preference of L-DRN rats in both conditions was always higher than that of SL-DRN rats. These results suggest that electrolytic lesion of the DRN overcomes a tonic inhibitory component of sodium appetite.http://www.scielo.br/scielo.php?script=sci_arttext&pid=S0100-879X2003001200013Sodium appetiteWater intakeDorsal raphe nucleusSerotonergic systemElectrolytic lesionRats |
collection |
DOAJ |
language |
English |
format |
Article |
sources |
DOAJ |
author |
E.L. Olivares R.H. Costa-e-Sousa H.R. Cavalcante-Lima H.R.C. Lima P.L. Cedraz-Mercez L.C. Reis |
spellingShingle |
E.L. Olivares R.H. Costa-e-Sousa H.R. Cavalcante-Lima H.R.C. Lima P.L. Cedraz-Mercez L.C. Reis Effect of electrolytic lesion of the dorsal raphe nucleus on water intake and sodium appetite Brazilian Journal of Medical and Biological Research Sodium appetite Water intake Dorsal raphe nucleus Serotonergic system Electrolytic lesion Rats |
author_facet |
E.L. Olivares R.H. Costa-e-Sousa H.R. Cavalcante-Lima H.R.C. Lima P.L. Cedraz-Mercez L.C. Reis |
author_sort |
E.L. Olivares |
title |
Effect of electrolytic lesion of the dorsal raphe nucleus on water intake and sodium appetite |
title_short |
Effect of electrolytic lesion of the dorsal raphe nucleus on water intake and sodium appetite |
title_full |
Effect of electrolytic lesion of the dorsal raphe nucleus on water intake and sodium appetite |
title_fullStr |
Effect of electrolytic lesion of the dorsal raphe nucleus on water intake and sodium appetite |
title_full_unstemmed |
Effect of electrolytic lesion of the dorsal raphe nucleus on water intake and sodium appetite |
title_sort |
effect of electrolytic lesion of the dorsal raphe nucleus on water intake and sodium appetite |
publisher |
Associação Brasileira de Divulgação Científica |
series |
Brazilian Journal of Medical and Biological Research |
issn |
0100-879X 1414-431X |
publishDate |
2003-12-01 |
description |
The present study determined the effect of an electrolytic lesion of the dorsal raphe nucleus (DRN) on water intake and sodium appetite. Male Wistar rats weighing 290-320 g with a lesion of the DRN (L-DRN), performed two days before experiments and confirmed by histology at the end of the experiments, presented increased sensitivity to the dehydration induced by fluid deprivation. The cumulative water intake of L-DRN rats reached 23.3 ± 1.9 ml (a 79% increase, N = 9) while sham-lesioned rats (SL-DRN) did not exceed 13.0 ± 1.0 ml (N = 11, P < 0.0001) after 5 h. The L-DRN rats treated with isoproterenol (300 µg kg-1 ml-1, sc) exhibited an increase in water intake that persisted throughout the experimental period (L-DRN, 15.7 ± 1.47 ml, N = 9 vs SL-DRN, 9.3 ± 1.8 ml, N = 11, P < 0.05). The L-DRN rats also showed an increased spontaneous sodium appetite during the entire period of assessment. The intake of 0.3 M NaCl after 12, 24, 36 and 72 h by the L-DRN rats was always higher than 20.2 ± 4.45 ml (N = 10), while the intake by SL-DRN was always lower than 2.45 ± 0.86 ml (N = 10, P < 0.00001). Sodium- and water-depleted L-DRN rats also exhibited an increased sodium appetite (13.9 ± 2.0 ml, N = 11) compared to SL-DRN (4.6 ± 0.64 ml, N = 11) after 120 min of observation (P < 0.02). The sodium preference of L-DRN rats in both conditions was always higher than that of SL-DRN rats. These results suggest that electrolytic lesion of the DRN overcomes a tonic inhibitory component of sodium appetite. |
topic |
Sodium appetite Water intake Dorsal raphe nucleus Serotonergic system Electrolytic lesion Rats |
url |
http://www.scielo.br/scielo.php?script=sci_arttext&pid=S0100-879X2003001200013 |
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