GABA in the central amygdaloid nucleus modulates the electrolyte excretion and hormonal responses to blood volume expansion in rats
We investigated the involvement of GABAergic mechanisms of the central amygdaloid nucleus (CeA) in unanesthetized rats subjected to acute isotonic or hypertonic blood volume expansion (BVE). Male Wistar rats bearing cannulas unilaterally implanted in the CeA were treated with vehicle, muscimol (0.2...
| Main Authors: | , , |
|---|---|
| Format: | Article |
| Language: | English |
| Published: |
Associação Brasileira de Divulgação Científica
2009-01-01
|
| Series: | Brazilian Journal of Medical and Biological Research |
| Subjects: | |
| Online Access: | http://www.scielo.br/scielo.php?script=sci_arttext&pid=S0100-879X2009000100016 |
| _version_ | 1818546786338340864 |
|---|---|
| author | L.O. Margatho L.L.K. Elias J. Antunes-Rodrigues |
| author_facet | L.O. Margatho L.L.K. Elias J. Antunes-Rodrigues |
| author_sort | L.O. Margatho |
| collection | DOAJ |
| description | We investigated the involvement of GABAergic mechanisms of the central amygdaloid nucleus (CeA) in unanesthetized rats subjected to acute isotonic or hypertonic blood volume expansion (BVE). Male Wistar rats bearing cannulas unilaterally implanted in the CeA were treated with vehicle, muscimol (0.2 nmol/0.2 µL) or bicuculline (1.6 nmol/0.2 µL) in the CeA, followed by isotonic or hypertonic BVE (0.15 or 0.3 M NaCl, 2 mL/100 g body weight over 1 min). The vehicle-treated group showed an increase in sodium excretion, urinary volume, plasma oxytocin (OT), and atrial natriuretic peptide (ANP) levels compared to control rats. Muscimol reduced the effects of BVE on sodium excretion (isotonic: 2.4 ± 0.3 vs vehicle: 4.8 ± 0.2 and hypertonic: 4.0 ± 0.7 vs vehicle: 8.7 ± 0.6 µEq·100 g-1·40 min-1); urinary volume after hypertonic BVE (83.8 ± 10 vs vehicle: 255.6 ± 16.5 µL·100 g-1·40 min-1); plasma OT levels (isotonic: 15.3 ± 0.6 vs vehicle: 19.3 ± 1 and hypertonic: 26.5 ± 2.6 vs vehicle: 48 ± 3 pg/mL), and ANP levels (isotonic: 97 ± 12.8 vs vehicle: 258.3 ± 28.1 and hypertonic: 160 ± 14.6 vs vehicle: 318 ± 16.3 pg/mL). Bicuculline reduced the effects of isotonic or hypertonic BVE on urinary volume and ANP levels compared to vehicle-treated rats. However, bicuculline enhanced the effects of hypertonic BVE on plasma OT levels. These data suggest that CeA GABAergic mechanisms are involved in the control of ANP and OT secretion, as well as in sodium and water excretion in response to isotonic or hypertonic blood volume expansion. |
| first_indexed | 2024-12-12T07:57:53Z |
| format | Article |
| id | doaj.art-9d420d44e9814d6eb862df0735ec3f41 |
| institution | Directory Open Access Journal |
| issn | 0100-879X 1414-431X |
| language | English |
| last_indexed | 2024-12-12T07:57:53Z |
| publishDate | 2009-01-01 |
| publisher | Associação Brasileira de Divulgação Científica |
| record_format | Article |
| series | Brazilian Journal of Medical and Biological Research |
| spelling | doaj.art-9d420d44e9814d6eb862df0735ec3f412022-12-22T00:32:16ZengAssociação Brasileira de Divulgação CientíficaBrazilian Journal of Medical and Biological Research0100-879X1414-431X2009-01-01421114121GABA in the central amygdaloid nucleus modulates the electrolyte excretion and hormonal responses to blood volume expansion in ratsL.O. MargathoL.L.K. EliasJ. Antunes-RodriguesWe investigated the involvement of GABAergic mechanisms of the central amygdaloid nucleus (CeA) in unanesthetized rats subjected to acute isotonic or hypertonic blood volume expansion (BVE). Male Wistar rats bearing cannulas unilaterally implanted in the CeA were treated with vehicle, muscimol (0.2 nmol/0.2 µL) or bicuculline (1.6 nmol/0.2 µL) in the CeA, followed by isotonic or hypertonic BVE (0.15 or 0.3 M NaCl, 2 mL/100 g body weight over 1 min). The vehicle-treated group showed an increase in sodium excretion, urinary volume, plasma oxytocin (OT), and atrial natriuretic peptide (ANP) levels compared to control rats. Muscimol reduced the effects of BVE on sodium excretion (isotonic: 2.4 ± 0.3 vs vehicle: 4.8 ± 0.2 and hypertonic: 4.0 ± 0.7 vs vehicle: 8.7 ± 0.6 µEq·100 g-1·40 min-1); urinary volume after hypertonic BVE (83.8 ± 10 vs vehicle: 255.6 ± 16.5 µL·100 g-1·40 min-1); plasma OT levels (isotonic: 15.3 ± 0.6 vs vehicle: 19.3 ± 1 and hypertonic: 26.5 ± 2.6 vs vehicle: 48 ± 3 pg/mL), and ANP levels (isotonic: 97 ± 12.8 vs vehicle: 258.3 ± 28.1 and hypertonic: 160 ± 14.6 vs vehicle: 318 ± 16.3 pg/mL). Bicuculline reduced the effects of isotonic or hypertonic BVE on urinary volume and ANP levels compared to vehicle-treated rats. However, bicuculline enhanced the effects of hypertonic BVE on plasma OT levels. These data suggest that CeA GABAergic mechanisms are involved in the control of ANP and OT secretion, as well as in sodium and water excretion in response to isotonic or hypertonic blood volume expansion.http://www.scielo.br/scielo.php?script=sci_arttext&pid=S0100-879X2009000100016Central amygdaloid nucleusNatriuresisUrine outputOxytocinAtrial natriuretic peptide |
| spellingShingle | L.O. Margatho L.L.K. Elias J. Antunes-Rodrigues GABA in the central amygdaloid nucleus modulates the electrolyte excretion and hormonal responses to blood volume expansion in rats Brazilian Journal of Medical and Biological Research Central amygdaloid nucleus Natriuresis Urine output Oxytocin Atrial natriuretic peptide |
| title | GABA in the central amygdaloid nucleus modulates the electrolyte excretion and hormonal responses to blood volume expansion in rats |
| title_full | GABA in the central amygdaloid nucleus modulates the electrolyte excretion and hormonal responses to blood volume expansion in rats |
| title_fullStr | GABA in the central amygdaloid nucleus modulates the electrolyte excretion and hormonal responses to blood volume expansion in rats |
| title_full_unstemmed | GABA in the central amygdaloid nucleus modulates the electrolyte excretion and hormonal responses to blood volume expansion in rats |
| title_short | GABA in the central amygdaloid nucleus modulates the electrolyte excretion and hormonal responses to blood volume expansion in rats |
| title_sort | gaba in the central amygdaloid nucleus modulates the electrolyte excretion and hormonal responses to blood volume expansion in rats |
| topic | Central amygdaloid nucleus Natriuresis Urine output Oxytocin Atrial natriuretic peptide |
| url | http://www.scielo.br/scielo.php?script=sci_arttext&pid=S0100-879X2009000100016 |
| work_keys_str_mv | AT lomargatho gabainthecentralamygdaloidnucleusmodulatestheelectrolyteexcretionandhormonalresponsestobloodvolumeexpansioninrats AT llkelias gabainthecentralamygdaloidnucleusmodulatestheelectrolyteexcretionandhormonalresponsestobloodvolumeexpansioninrats AT jantunesrodrigues gabainthecentralamygdaloidnucleusmodulatestheelectrolyteexcretionandhormonalresponsestobloodvolumeexpansioninrats |