Lesion of the anteroventral third ventricle region abolishes the beneficial effects of hypertonic saline on hemorrhagic shock in rats

Hemodynamic Responses Elicited By γ2-MSH or Blood Replacement in Hemorrhaged Rats

“…Lesions of the anteroventral region of the third ventricle (AV3V) region impair ␥ 2 -MSH-induced pressor responses [20]. These lesions also impair the recovery of MAP produced by systemic injections of hypertonic saline in hemorrhaged rats [37,38]. These findings suggest that the AV3V region plays a role in the autonomic adjustments produced by ␥ 2 -MSH and hypertonic saline in hemorrhaged rats.…”

Hemodynamic responses elicited by systemic injections of isotonic and hypertonic saline in hemorrhaged rats

“…It would seem feasible that the administration of H-saline leads to exaggerated vasoconstrictor efficacy of neurogenic-derived catecholamines and relevant circulating factors. Lesions of the anteroventral region of the third ventricle (AV3V) impair the recovery of MAP induced by H-saline (7.5% NaCl, 4 ml/kg) in HEM rats (Barbosa et al, 1990, 1992). As such, it is likely that the beneficial actions of H-saline in our study also involved changes in the activities of AV3V neurons that control neurogenic outflow and the release of hormones regulating vascular tone and fluid/salt balance such as angiotensin II and arginine vasopressin (see Barbosa et al, 1990, 1992).…”

“…Lesions of the anteroventral region of the third ventricle (AV3V) impair the recovery of MAP induced by H-saline (7.5% NaCl, 4 ml/kg) in HEM rats (Barbosa et al, 1990, 1992). As such, it is likely that the beneficial actions of H-saline in our study also involved changes in the activities of AV3V neurons that control neurogenic outflow and the release of hormones regulating vascular tone and fluid/salt balance such as angiotensin II and arginine vasopressin (see Barbosa et al, 1990, 1992). It should be mentioned that systemic injections of γ 2 -melanocyte-stimulating hormone (γ 2 -MSH) elicits equivalent increases in resistance in the renal, mesenteric and hindquarter vascular beds of pentobarbital-anesthetized rats (Whalen et al, 2007).…”

“…There is considerable information as to effects of small volumes of isotonic saline (I-saline) and H-saline on MAP, CO and TPR in low CO-induced hypotension during HEM (Brooks, 1935; Nakayama et al, 1984; Smith et al, 1985; Maningas et al, 1986; Traveso et al, 1987; Hannon et al, 1989; Barbosa et al, 1990, 1992). However, although the changes in systemic vascular resistances during HEM in animals have received attention (see Liu et al, 2003; Whalen et al, 2007), nothing is known about the changes in systemic resistances elicited by administration of I-saline or H-saline in these rats.…”