Central administration of losartan effectively blocked the increase of blood pressure and drinking response induced by angiotensin II (Ang II) or carbachol. However, the relationship between angiotensin AT(1) receptors and the natriuresis induced by brain cholinergic stimuli is still not clear. The purpose of the study is to reveal the role of brain angiotensin AT(1) receptor in the carbachol-induced natriuresis and expression of neuronal nitric oxide synthase (nNOS) in the locus coeruleus (LC) and proximal convoluted tubule (PCT). Our results indicated that 40 min after intracerebroventricular (ICV) injection of carbachol (0.5 microg), urinary sodium excretion was significantly increased to 0.548+/-0.049 micromol x min(-1) x 100 g(-1). Immunohistochemistry showed that carbachol induced an increase of neuronal nitric oxide synthase immunoreactivity (nNOS-IR) in the LC and renal proximal tubular cells. After pretreatment with losartan (20 microg), carbachol-induced urinary sodium excretion was reduced to 0.249+/-0.067 micromol x min(-1) x 100 g(-1). The same was true for carbachol-induced increase of nNOS-IR in the LC and PCT. The present data suggest that ICV cholinergic stimulation could induce a natriuresis and upregulate the activity of nNOS in the LC and PCT. The blockade of AT(1) receptors might downregulate the effects induced by carbachol in the LC and PCT. Consequently, we provide a new evidence that brain angiotensinergic pathway and NO-dependent neural pathway contribute to the natriuresis following brain cholinergic stimulation and thus play an important role in the regulation of fluid homeostasis. Furthermore, the final effect of nitric oxide on proximal tubular sodium reabsorption participated in the natriuresis induced by brain cholinergic stimulation.
- MeSH
- blokátory receptorů AT1 pro angiotensin II aplikace a dávkování MeSH
- časové faktory MeSH
- cholinergní agonisté aplikace a dávkování MeSH
- enzymová indukce MeSH
- injekce intraventrikulární MeSH
- karbachol aplikace a dávkování MeSH
- krysa rodu Rattus MeSH
- locus coeruleus účinky léků enzymologie metabolismus MeSH
- losartan aplikace a dávkování MeSH
- natriuréza účinky léků MeSH
- oxid dusnatý metabolismus MeSH
- potkani Sprague-Dawley MeSH
- proximální tubuly ledvin účinky léků enzymologie MeSH
- receptor angiotensinu typ 1 metabolismus MeSH
- sodík moč MeSH
- synthasa oxidu dusnatého, typ I MeSH
- synthasa oxidu dusnatého biosyntéza MeSH
- zvířata MeSH
- Check Tag
- krysa rodu Rattus MeSH
- mužské pohlaví MeSH
- zvířata MeSH
- Publikační typ
- časopisecké články MeSH
- práce podpořená grantem MeSH
- Názvy látek
- blokátory receptorů AT1 pro angiotensin II MeSH
- cholinergní agonisté MeSH
- karbachol MeSH
- losartan MeSH
- Nos1 protein, rat MeSH Prohlížeč
- oxid dusnatý MeSH
- receptor angiotensinu typ 1 MeSH
- sodík MeSH
- synthasa oxidu dusnatého, typ I MeSH
- synthasa oxidu dusnatého MeSH
The development of heart rate and of muscarinic and beta-adrenergic receptors in chick heart ventricles in the last third of in ovo ontogenesis has been studied. The development of these two types of autonomic receptors does not proceed in parallel. While muscarinic receptors are stable between days 13 and 17, beta-adrenergic receptors significantly decrease in this period. Muscarinic receptors increase their number from the 17th day, and the highest density can be seen after hatching. beta-adrenergic receptors, on the contrary, do not change their density between days 17 and 19, but similarly to muscarinic receptors they increase after hatching (the density after hatching is approximately the same as on the day 13 of embryonic development). We have shown previously that stimulation of one receptor type in the system of autonomic receptors in the heart changes not only the appropriate type of receptor but also the density of the other one. We therefore wondered the information about this in the organism in development. Here we show that when we have infused the eggs in developmental period mentioned above there was no cross-regulation and that muscarinic receptors do not down-regulate. Up-regulation of muscarinic receptors was maintained when the eggs were infused by carbachol from the 13th to 14th day of in ovo development. This muscarinic receptor up-regulation was accompanied with paradoxical increase in heart rate. These events are not proteinkinase (PKC) dependent, as bisindolylmaleimide (PKC inhibitor) do not prevent these changes.
- MeSH
- beta-adrenergní receptory účinky léků fyziologie MeSH
- cholinergní agonisté aplikace a dávkování farmakologie MeSH
- indoly aplikace a dávkování farmakologie MeSH
- inhibitory proteinkinas farmakologie MeSH
- karbachol aplikace a dávkování farmakologie MeSH
- kuřecí embryo MeSH
- maleimidy aplikace a dávkování farmakologie MeSH
- receptory muskarinové účinky léků fyziologie MeSH
- srdce embryologie inervace MeSH
- srdeční frekvence účinky léků fyziologie MeSH
- zvířata MeSH
- Check Tag
- kuřecí embryo MeSH
- zvířata MeSH
- Publikační typ
- časopisecké články MeSH
- práce podpořená grantem MeSH
- Názvy látek
- beta-adrenergní receptory MeSH
- bisindolylmaleimide MeSH Prohlížeč
- cholinergní agonisté MeSH
- indoly MeSH
- inhibitory proteinkinas MeSH
- karbachol MeSH
- maleimidy MeSH
- receptory muskarinové MeSH
- MeSH
- acetylcholin aplikace a dávkování MeSH
- extrakce katarakty MeSH
- karbachol aplikace a dávkování MeSH
- lidé MeSH
- pooperační péče MeSH
- přední komora oční * MeSH
- Check Tag
- lidé MeSH
- Publikační typ
- anglický abstrakt MeSH
- časopisecké články MeSH
- srovnávací studie MeSH
- Názvy látek
- acetylcholin MeSH
- karbachol MeSH
