The effects of peptide and nonpeptide antagonists of angiotensin II receptors on the level of brain biogenic monoamines in rats with angiotensin II-induced increase of water intake.
The effects of peptide and nonpeptide angiotensin II (Ang II)-receptor antagonists (losartan, EXP-3174, saralasin and sarmesin) on the levels of the biogenic monoamines dopamine, noradrenaline and serotonin in the frontal cortex, striatum, hypothalamus and hippocampus of rats with Ang II-induced water intake were investigated. Ang II administered i.c.v. at a dose inducing drinking behavior in rats significantly changed the levels of biogenic monoamines. The latter were also significantly affected by the Ang II-receptor antagonists, as in most cases the drugs antagonized the effect of Ang II. Most pronounced were the effects of Ang II and Ang II-receptor antagonists on the dopamine levels. These levels were reduced to zero after Ang II in all brain structures studied. The drugs tested increased the dopamine levels, restoring their values to the values in vehicle-injected rats. Ang II-receptor antagonists exerted mosaic effects on noradrenaline and 5-HT (serotonin) levels depending on both--the type of biogenic monoamine and the brain structure. There was no relationship between the inhibition of Ang II-induced water intake and the changes in the levels of brain biogenic monoamines under the effect of the Ang II-receptor antagonists. These antagonists may play a role in the modulation of brain monoaminergic neurotransmitter systems.
Stancheva
S
S
Radioisotope Laboratory, Institute of Physiology, Bulgarian Academy of Sciences, Sofia, Bulgaria. fany@iph.bio.bas.bg
Alova
L
L
Velkova
M
M
Georgiev
V
V
D000704:Analysis of Variance; D057911:Angiotensin Receptor Antagonists; D000818:Animals; D015306:Biogenic Monoamines / Q000378:metabolism*; D001921:Brain / Q000187:drug effects* / Q000378:metabolism; D004326:Drinking / Q000187:drug effects; D007276:Injections, Intraventricular; D008297:Male; D051381:Rats; D017208:Rats, Wistar; D011945:Receptors, Angiotensin / Q000502:physiology
D057911:Angiotensin Receptor Antagonists; D015306:Biogenic Monoamines; D011945:Receptors, Angiotensin