Psychotropic effects of angiotensin II N-terminal fragments: Asp-Arg-Val-Tyr-Ile-His and Arg-Val-Tyr-Ile-His in rats.
In this study the effects of angiotensin II (AII) angiotensin II hexapeptide [AII(1-6)] and angiotensin II pentapeptide [AII(2-6)] on the motility, stereotypy, learning of conditioned avoidance responses (CARs) and recall of a passive behavior making it possible to avoid aversive stimulation in rats, were compared. All the peptides were injected into the lateral cerebral ventricle (icv) in a dose of 1 nmol. AII caused a statistically significant increase in the number of crossings, rearings, and bar approaches in an open field whereas [AII(1-6)] and [AII(2-6)] were inactive in this test. The stereotypic behavior induced by an intraperitoneal (ip) injection of apomorphine (1 mg/kg) and amphetamine (7.5 mg/kg) was statistically significantly enhanced only in the rats which received AII icv. The application of AII, but not that of [AII(1-6)] and [AII(2-6)] resulted in a quicker acquisition of the CARs. A better recall of passive avoidance was achieved only by AII, while the fragments [AII(1-6)] and [AII(2-6)] had no effect. These findings indicate that the 1-6 and 2-6 fragments of AII do not possess a psychotropic activity like that of the parent octapeptide.
Hoły
Z
Z
Department of Pharmacology, Medical Academy, Białystok, Poland.
Braszko
J
J
Wiśniewski
K
K
D000595:Amino Acid Sequence; D000661:Amphetamine / Q000494:pharmacology; D000804:Angiotensin II / Q000494:pharmacology*; D000818:Animals; D001058:Apomorphine / Q000494:pharmacology; D001362:Avoidance Learning / Q000187:drug effects; D001921:Brain / Q000187:drug effects*; D003214:Conditioning, Classical / Q000187:drug effects; D007276:Injections, Intraventricular; D008297:Male; D008969:Molecular Sequence Data; D009043:Motor Activity / Q000187:drug effects; D009842:Oligopeptides / Q000494:pharmacology; D010446:Peptide Fragments; D011619:Psychotropic Drugs; D051381:Rats; D017208:Rats, Wistar
D009842:Oligopeptides; D010446:Peptide Fragments; D011619:Psychotropic Drugs; D000804:Angiotensin II; D000661:Amphetamine; D001058:Apomorphine