Cardiovascular adjustments induced by hypertonic saline in hemorrhagic rats: Involvement of carotid body chemoreceptors

• Published in: Autonomic neuroscience Vol. 160; no. 1; pp. 37 - 41
• Main Authors: Pedrino, Gustavo R, Rossi, Marcio V, Schoorlemmer, Guus H.M, Lopes, Oswaldo U, Cravo, Sergio L
• Format: Journal Article
• Language: English
• Published: Amsterdam Elsevier B.V 24.02.2011; Elsevier
• Subjects: Advanced Basic Science; Animals; Arterial blood pressure and heart rate; Biological and medical sciences; Blood Pressure - physiology; Carotid Body - physiopathology; Carotid body chemoreceptors; Fundamental and applied biological sciences. Psychology; Hemodynamics - physiology; Hemorrhage - physiopathology; Hypertonic saline; Hypovolemia - physiopathology; Hypovolemic hemorrhage; Male; Medical Education; Peripheral nervous system. Autonomic nervous system. Neuromuscular transmission. Ganglionic transmission. Electric organ; Rats; Rats, Wistar; Saline Solution, Hypertonic - pharmacology; Shock, Hemorrhagic - physiopathology; Vertebrates: nervous system and sense organs; Hypertonic saline; Hypovolemic hemorrhage; Carotid body chemoreceptors; Arterial blood pressure and heart rate; Rat; Rodentia; Hemorrhage; Chemoreceptor; Heart rate; Vertebrata; Mammalia; Autonomic nervous system; Animal; Arterial pressure; Blood pressure; Hemodynamics; Carotid body
• ISSN: 1566-0702; 1872-7484
• DOI: 10.1016/j.autneu.2010.11.009

Abstract The peripheral hyperosmolarity elicited by intravenous infusion of hypertonic saline brings potential benefits to the treatment of hemorrhage. The neural mechanisms involved in these beneficial effects remain unknown. The present study examines the role of carotid chemoreceptors in cardiovascular responses induced by hypertonic saline after hypovolemic hemorrhage in rats. Male Wistar rats (300–400 g) were anesthetized with thiopental, and instrumented for recording of mean arterial pressure. Arterial pressure was reduced to 60 mm Hg by withdrawal of arterial blood over 10 min, and maintained at this level for 60 min by withdrawal or infusion of blood. In control rats (n = 8) with intact chemoreceptors, the subsequent intravenous infusion of hypertonic saline (3 M NaCl, 1.8 ml kg − 1 body weight, in 2 min) restored blood pressure (pressure increased from 61 ± 4 to 118 ± 5 mm Hg). In experimental rats (n = 8), the carotid body arteries were tied, 30 min after the beginning of the hypotensive phase, leaving the carotid chemoreceptors ischemic. In these rats, hypertonic saline failed to restore blood pressure (pressure increased from 55 ± 1 to 70 ± 6 mm Hg). These findings suggest that the restoration of blood pressure after hypovolemic hemorrhage induced by hypertonic saline depends on intact carotid chemoreceptors.