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Cardiovascular adjustments induced by hypertonic saline resuscitation in rats submitted to hemorrhage shock: involvement of neural structures
Author(s) -
de Almeida Costa Eloisa Ferreira,
Pedrino Gustavo Rodrigues,
Lopes Oswaldo Ubríaco,
Cravo Sergio L
Publication year - 2007
Publication title -
the faseb journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.709
H-Index - 277
eISSN - 1530-6860
pISSN - 0892-6638
DOI - 10.1096/fasebj.21.6.a1279
Subject(s) - baroreceptor , mean arterial pressure , medicine , anesthesia , hypertonic saline , resuscitation , denervation , saline , blood pressure , shock (circulatory) , carotid sinus , femoral artery , heart rate , reflex
The peripheral hyperosmolarity elicited by intravenous infusion of hypertonic saline (HS) brings several benefits to the treatment of hemorrhagic shock. However the neural mechanisms involved in this resuscitation remains unknown. The present study sought to determine the effects of selective baroreceptor denervation on arterial pressure response during HS resuscitation in rats submitted to hemorrhagic shock. Male Wistar rats (280‐320g) were anesthetized with thiopental sodium (40mg/Kg, iv), the femoral artery and jugular vein were cannulated for mean arterial pressure (MAP) recording and HS infusion (3M NaCl, 0.18mL/100g bw, in 60s), respectively. The hemorrhagic shock was obtained by withdrawal of blood over 30 min until a MAP of 60 mmHg was obtained. Subsequent blood was withdrawn or reinfused as needed to maintain this MAP for more 30 min. The results demonstrated that in sham group (N=12), HS infusion increased MAP to values close to the baseline (from 65 ± 3 to 112 ± 3 mm Hg, 10 min after HS). In the aortic denervation group (N=10), HS infusion also increased MAP (from 54 ± 3 to 112 ± 5 mm Hg, 10 min after HS). In contrast, in the carotid denervation group (N=8), the increased of MAP induced by HS infusion was abolished (from 53 ± 3 to 73 ± 12 mm Hg, 10 min after HS). These results indicate that in hemorrhaged rats, HS infusion produced a pressor effect and that this is likely to be mediated through the carotid baroreceptors, but not through the aortic baroreceptors. Supported by: CAPES and CNPq