title: Effects of central osmotic stimulation on vasopressin and enkephalin release into the blood and cerebrospinal fluid and blood pressure.
abstract: To assess the central effect of hypertonic NaCl on the release of vasopressin (AVP) and methionine enkephalin-like substances into the blood and cerebrospinal fluid, and on blood pressure, ventriculocisternal perfusion (0.25 ml/min, 60 min) was performed in anesthetized dogs with artificial cerebrospinal fluid (CSF), either isotonic (300 mosmol/kg) or hypertonic (600 and 1200 mosmol/kg). The effect of central administration of a V1-AVP antagonist on the central osmotic challenge was also studied. In dogs, given 600 mosmol/kg, CSF osmolality increased with a concomitant rise in mean arterial pressure and plasma AVP concentrations. Plasma osmolality, heart rate, CSF AVP and plasma and CSF methionine enkephalin-like substances showed no significant change. In dogs, given 1200 mosmol/kg, the CSF osmolality increase was accompanied by a rise in mean arterial pressure, heart rate, plasma AVP and CSF AVP. Plasma osmolality and plasma and CSF methionine-enkephalin-like substances did not change significantly. A V1-AVP antagonist given centrally attenuated the rise in mean arterial pressure induced by osmotic challenge. In dogs, given 300 mosmol/kg, no parameters changed significantly except for a gradual fall in heart rate. These results suggest that central osmotic stimulation by hypertonic NaCl increases blood pressure, heart rate and the release of AVP, but not methionine enkephalin-like substances, into the blood and CSF, and a V1-blocker given centrally attenuates the pressor response.
authors.affiliation: Second Department of Internal Medicine, Tohoku University School of Medicine, Sendai, Japan.
authors.forename: K
authors.initials: K
authors.lastname: Ota
authors.forename: T
authors.initials: T
authors.lastname: Kimura
authors.forename: K
authors.initials: K
authors.lastname: Matsui
authors.forename: K
authors.initials: K
authors.lastname: Iitake
authors.forename: M
authors.initials: M
authors.lastname: Shoji
authors.forename: M
authors.initials: M
authors.lastname: Inoue
authors.forename: K
authors.initials: K
authors.lastname: Sato
authors.forename: M
authors.initials: M
authors.lastname: Ohta
authors.forename: T
authors.initials: T
authors.lastname: Yamamoto
authors.forename: K
authors.initials: K
authors.lastname: Yoshinaga
mesh_terms: D000818:Animals; D001794:Blood Pressure / Q000187:drug effects*; D002552:Cerebral Ventricles; D004285:Dogs; D004744:Enkephalin, Methionine / Q000032:analysis* / Q000097:blood / Q000134:cerebrospinal fluid; D005260:Female; D006339:Heart Rate / Q000187:drug effects; D009994:Osmolar Concentration; D010477:Perfusion; D012462:Saline Solution, Hypertonic / Q000008:administration & dosage* / Q000494:pharmacology; D014667:Vasopressins / Q000032:analysis* / Q000097:blood / Q000134:cerebrospinal fluid; D014882:Water-Electrolyte Balance / Q000187:drug effects*
chemical_list: D012462:Saline Solution, Hypertonic; D014667:Vasopressins; D004744:Enkephalin, Methionine