Psychotropic activity of angiotensin II and its fragments Val-Tyr-Ile-NH2 and Val-Tyr-Ile-His-NH2.
Angiotensin II (A II) significantly enhanced the motor activity of rats in the open field as measured by forward locomotion, rearings and bar approaches while the tripeptide [A II(3-5)] and the tetrapeptide [A II(3-6)] were ineffective in this test. Also, the stereotyped behavior produced by apomorphine (2 mg/kg) or amphetamine (6.5 mg/kg), both given intraperitoneally, was significantly more intense in rats receiving an icv injection of A II but not A II(3-5) or A II(3-6). A II significantly increased the rate of acquisition of active avoidance while AII(3-5) and AII(3-6) were ineffective. Finally, a remarkable improvement of performance in the passive avoidance situation was caused by AII, and none by AII(3-5) and AII(3-6). These results show that 3-5 and 3-6 fragments of AII are not responsible for the psychotropic activity of their parent octapeptide and suggest that AII(3-7) pentapeptide should be the fragment in question.
Własienko
J
J
Department of Pharmacology, Chair of Pharmacology, Medical Academy, Białystok, Poland.
Braszko
J J
JJ
Koziołkiewicz
W
W
Janecka
A
A
Wiśniewski
K
K
D000595:Amino Acid Sequence; D000804:Angiotensin II / Q000494:pharmacology*; D000818:Animals; D001362:Avoidance Learning / Q000187:drug effects; D005106:Exploratory Behavior / Q000187:drug effects; D008297:Male; D008969:Molecular Sequence Data; D009043:Motor Activity / Q000187:drug effects; D010446:Peptide Fragments / Q000494:pharmacology*; D011619:Psychotropic Drugs; D051381:Rats; D011919:Rats, Inbred Strains; D013239:Stereotyped Behavior / Q000187:drug effects
D010446:Peptide Fragments; D011619:Psychotropic Drugs; D000804:Angiotensin II