Effects of [Arg8]-vasopressin on regional cerebral blood flow in spontaneously hypertensive rats.
The effects of [Arg(8)]-vasopressin (AVP) and related compounds on regional cerebral blood flow (rCBF) in the hippocampus were studied using conscious spontaneously hypertensive rats (SHR). rCBF in the hippocampus decreased gradually with age in proportion to an increase in mean blood pressure. Subcutaneous injection of AVP caused a dose-dependent increase in rCBF in the hippocampus. The effects of the metabolic fragments AVP4-9 and AVP4-8 on rCBF were relatively weak. OPC-31260, a vasopressin V(2) antagonist, antagonized the AVP-induced increase in rCBF in the hippocampus. Furthermore, subcutaneous injection of DDAVP, a V(2) agonist, increased rCBF in the hippocampus. On the other hand, the AVP-induced increase in rCBF in the hippocampus was not antagonized by OPC-21268, a vasopressin V(1) antagonist. Intracerebroventricular injection of AVP caused no significant changes in rCBF in the hippocampus, even at a dose of 10 ng/site.
Department of Pharmacology, Faculty of Pharmaceutical Sciences, Okayama University, Okayama, Japan.
N
N
Azuma
Y
Y
Sugimoto
M
M
Mio
K
K
Shinomiya
C
C
Kamei
D000818:Animals; D001127:Arginine Vasopressin / Q000494:pharmacology*; D002560:Cerebrovascular Circulation / Q000187:drug effects*; D007276:Injections, Intraventricular; D008297:Male; D010446:Peptide Fragments / Q000494:pharmacology*; D051381:Rats; D011918:Rats, Inbred SHR; D014662:Vasoconstrictor Agents / Q000494:pharmacology*
D010446:Peptide Fragments; D014662:Vasoconstrictor Agents; D001127:Arginine Vasopressin; C045881:argipressin (4-9)