title: Neural reflex hypotension induced by very small dose of hypertonic NaCl solution in rats.
abstract: Although the precise mechanisms of transient hypotension after intravenous infusion of hypertonic saline (HTS) are not yet clarified, a rapid infusion of HTS is widely used as the initial therapy of hypovolemia. We investigated the effect of the intravenous infusion of a small dose of 0.97-9.7% NaCl solutions in anesthetized rats. Intravenous infusion of HTS at a rate of 0.3 ml/kg/min for 1 min produced the transient hypotension lasting for several minutes. The depressor response to HTS was not abolished by bilateral cervical vagotomy. The HTS infusion into the femoral vein evoked the depressor response with a larger magnitude and a shorter latency than that into the aortic arch. While the arterial baroreceptor pressure was kept constant at the baseline level of systemic arterial pressure, HTS-induced hypotension was significantly augmented. The gain factor of the arterial baroreflex was reduced by intravenous HTS. Pretreatment with bretylium tosylate completely abolished the depressor response without affecting the baseline level of arterial pressure. These results suggest that the depressor response to the very small dose of intravenous HTS is the sympathosympathetic neural reflex with cardiopulmonary afferents and vasomotor efferents.
authors.affiliation: Department of Medical Function, Dalian Medical University, Lushun 116044, Dalian, Liaoning, People's Republic of China. dongmeizhang_2000@yahoo.com
authors.forename: Dongmei
authors.initials: D
authors.lastname: Zhang
authors.forename: Takayuki
authors.initials: T
authors.lastname: Sato
authors.forename: Dezheng
authors.initials: D
authors.lastname: Gong
authors.forename: Lei
authors.initials: L
authors.lastname: Fu
authors.forename: Shufang
authors.initials: S
authors.lastname: Dai
authors.forename: Hong
authors.initials: H
authors.lastname: Xu
authors.forename: Qiong
authors.initials: Q
authors.lastname: Wu
authors.forename: Dongmei
authors.initials: D
authors.lastname: Wang
authors.forename: Yan
authors.initials: Y
authors.lastname: Peng
authors.forename: Yiping
authors.initials: Y
authors.lastname: Sun
mesh_terms: D018674:Adrenergic Antagonists / Q000494:pharmacology; D000818:Animals; D017704:Baroreflex / Q000187:drug effects* / Q000502:physiology*; D001950:Bretylium Tosylate / Q000494:pharmacology; D002346:Carotid Sinus / Q000187:drug effects / Q000502:physiology; D004305:Dose-Response Relationship, Drug; D007022:Hypotension / Q000139:chemically induced* / Q000503:physiopathology*; D020896:Hypovolemia / Q000503:physiopathology / Q000628:therapy; D007261:Infusions, Intra-Arterial; D007262:Infusions, Intravenous; D008297:Male; D051381:Rats; D017208:Rats, Wistar; D012462:Saline Solution, Hypertonic / Q000494:pharmacology*; D013564:Sympathetic Nervous System / Q000187:drug effects / Q000502:physiology; D014628:Vagotomy
chemical_list: D018674:Adrenergic Antagonists; D012462:Saline Solution, Hypertonic; D001950:Bretylium Tosylate