The effects of peptide and nonpeptide angiotensin II-receptor ligands on the activity of brain monoamine oxidase in water-repleted rats.
The effects of i.c.v. administered peptide and nonpeptide ANG II-receptor ligands (losartan, EXP 3174, saralasin and sarmesin) on monoamine oxidase A (MAO-A) and MAO-B activities in the frontal cortex, striatum, hypothalamus and hippocampus of water-repleted rats were investigated. Alterations in MAO-A and MAO-B activities were found in different rat brain regions after ANG II which depended on the isoenzyme type and brain structure. MAO-A activity significantly increased in the frontal cortex and hypothalamus, brain regions containing AT1 receptors, mainly. MAO-A and MAO-B activities were affected differently by all studied ANG II-receptor ligands, which in most cases antagonized the effect of ANG II (losartan, an AT1-nonpeptide receptor antagonist being the most effective). There was no clearcut relationship between the inhibition of ANG II-induced water intake and the changes of MAO-A and MAO-B activities under the effect of the ANG II-receptor antagonists studied.
Stancheva
S
S
Radioizotope Laboratory, Institute of Physiology, Bulgarian Academy of Sciences, Sofia, Bulgaria. fany@iph.bio.bas.bg
Alova
L
L
Georgiev
V
V
D000804:Angiotensin II / Q000031:analogs & derivatives* / Q000378:metabolism* / Q000494:pharmacology; D000818:Animals; D001834:Body Water / Q000502:physiology*; D001921:Brain / Q000201:enzymology*; D004326:Drinking / Q000187:drug effects; D007093:Imidazoles / Q000494:pharmacology; D007527:Isoenzymes / Q000378:metabolism; D008024:Ligands; D019808:Losartan / Q000494:pharmacology; D008297:Male; D008995:Monoamine Oxidase / Q000378:metabolism*; D010455:Peptides / Q000494:pharmacology*; D051381:Rats; D017208:Rats, Wistar; D011945:Receptors, Angiotensin / Q000187:drug effects / Q000378:metabolism*; D013777:Tetrazoles / Q000494:pharmacology
D007093:Imidazoles; D007527:Isoenzymes; D008024:Ligands; D010455:Peptides; D011945:Receptors, Angiotensin; D013777:Tetrazoles; D000804:Angiotensin II; C040420:angiotensin II, Sar(1)-Me-Tyr(4)-; D008995:Monoamine Oxidase; C066026:losartan carboxylic acid; D019808:Losartan