Clearance of vasopressin from cerebrospinal fluid to blood in chronically cannulated Brattleboro rats.
The antidiuretic effects of intravenous (i.v.) and intracerebroventricular (i.c.v.) infusions of vasopressin (AVP) were compared in chronically cannulated conscious Brattleboro rats. AVP infused i.c.v. for 6 h reduced urine volume and increased urinary Na+ and K+ concentrations. These antidiuretic responses to i.c.v. AVP were dose related in the range 3-12 ng/h and were delayed and prolonged when compared with i.v. infusions (0.33-3 ng/h) of this peptide. Comparison of the dose-response curves for both routes of administration demonstrated that the antidiuretic response to i.c.v. infusion of AVP was approximately 10-fold lower than to AVP given intravenously. Since measurable amounts of AVP-like material appeared in the urine during the antidiuretic response, we conclude that a significant amount of AVP infused into the cerebroventricular system reaches the bloodstream in a biologically active form.
D000818:Animals; D004231:Diuresis; D004305:Dose-Response Relationship, Drug; D005260:Female; D007263:Infusions, Parenteral; D007276:Injections, Intraventricular; D007700:Kinetics; D011188:Potassium / Q000652:urine; D051381:Rats; D011910:Rats, Brattleboro; D012964:Sodium / Q000652:urine; D014667:Vasopressins / Q000097:blood / Q000134:cerebrospinal fluid* / Q000494:pharmacology
D014667:Vasopressins; D012964:Sodium; D011188:Potassium