Substance P (SP) is a neuropeptide engaged in the signal transmission of neural C fibers afferents in the myocardium. The actions of SP in the heart are extensive and they are mediated by the neurokinin 1 receptor (NK1R), a member of the tachykinin subfamily of G-protein coupled receptors. The receptors have been found in the heart, but to our knowledge, their exact localization in the heart has not been described yet. Here, we investigated the presence of NK1R protein in separate rat heart compartments by means of western blot and its tissue distribution by means of immunofluorescence. Specificity of NK1R immunolabeling was controlled by preabsorption of the antiserum with its corresponding peptide. Additionally, we investigated abundance of gene for NK1R in separated heart chambers by means of quantitative real-time PCR (RT-PCR). Relative abundance of NK1R mRNA was expressed as a ratio of target gene Cq value to Cq value of control gene - beta-actin. Finally, we studied abundance of NK1R mRNA in different cell types of heart isolated by laser capture microdissection. Immunofluorescence showed NK1R immunoreactivity on the surface of some intracardiac neurons and smooth muscle cells of coronary vessels. The results of quantitative RT-PCR indicate abundance of mRNA for NK1R in all heart chambers with highest level in the left atrium. The presence of NK1R mRNA was detected in some samples of dissected intracardiac neurons, but not in cardiomyocytes or smooth muscle cells of coronary vessels. In the course of long-term diabetes, a significant downregulation of the NK1R mRNA was seen in the right atrium and upregulation in the right ventricle 53 weeks after the induction of diabetes. Our results indicate localization of NK1R in some intracardiac neurons and smooth muscle cells. Impaired transcription of the NK1R gene in the diabetic heart may be induced by unidentified genes or factors involved in the development of diabetic cardiomyopathy.

• Publikační typ
• časopisecké články MeSH

Both adrenomedullin and calcitonin gene-related peptide (CGRP) regulate vascular tone in the heart, being cardioprotective in hypoxia. Additionally, adrenomedullin exhibits antiproliferative and antiapoptotic functions in the myocardium, while CGRP exerts positive chronotropic effect. Their actions are mediated through the specific G protein-coupled receptor, CRLR, whose ligand affinity is determined by receptor activity modifying proteins RAMP1-3. CGRP binds to the complex formed by CRLR/RAMP1, whereas CRLR/RAMP2 and CRLR/RAMP3 serve as receptors for adrenomedullin. Here, we quantified expression of this signaling system in the rat heart and supplying sensory ganglia (dorsal root ganglia T1-T4 and vagal nodose ganglia) in streptozotocin-induced diabetes. In the course of diabetes, an increase of CRLR mRNA was noticed in the right ventricle 8 weeks and of RAMP3 mRNA in the left ventricle and right atrium 26 weeks after induction of diabetes. Relative expressions of other tested genes were not significantly altered. In the nodose vagal supplying specific cardiac afferents, but not in dorsal root ganglia which provide cardiac pain fibres, a small upregulation of CGRP expression was detected. In summary, the shifts observed in diabetes may favour a trend of a pronounced adrenomedullin signaling. These observations may provide a new possible therapeutic strategy for diabetic cardiomyopathy.

• MeSH
• adrenomedulin genetika   metabolismus   MeSH
• experimentální diabetes mellitus genetika   patologie   MeSH
• krysa rodu rattus MeSH
• messenger RNA genetika   metabolismus   MeSH
• myokard metabolismus   MeSH
• potkani Wistar MeSH
• protein podobný kalcitoninovému receptoru genetika   metabolismus   MeSH
• regulace genové exprese * MeSH
• senzorická ganglia metabolismus   MeSH
• signální transdukce MeSH
• zvířata MeSH
• Check Tag
• krysa rodu rattus MeSH
• ženské pohlaví MeSH
• zvířata MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH

BACKGROUND: Chronic renal failure is frequently associated with a high risk of sudden cardiac death due to dysfunction of the autonomic nervous system. The pathogenic mechanisms underlying the parasympathetic cardiac dysautonomia are not fully elucidated yet. METHODS: Chronic renal failure was induced in rats by 5/6 nephrectomy. Blood pressure, resting heart rate and plasma levels of creatinine, urea and asymmetric dimethylarginine (ADMA) were measured. To characterize the parasympathetic innervation of the heart, chronotropic responses to atropine, metipranolol and to vagal stimulation in the absence or presence of ADMA were investigated in vivo. In vitro, chronotropic and inotropic effects of carbachol and ADMA and mRNA expression of muscarinic M2 receptors, high affinity choline transporter (CHT1), vesicular acetylcholine transporter (VAChT) and choline acetyltransferase (ChAT) were assessed in the isolated cardiac tissues. RESULTS: In 5/6 nephrectomy rats, the resting heart rate was significantly higher and the parasympathetic tone, measured as the effect of atropine after administration of metipranolol was significantly lower than in control animals. Plasma ADMA levels were significantly elevated in the uraemic rats and significantly inversely correlated with the effect of atropine on the heart rate. No differences were revealed in the plasma norepinephrine concentrations, negative chronotropic responses to stimulation of the vagus nerves, chronotropic and inotropic responses to carbachol and the relative expression of M2 receptors, CHT1, VAChT and ChAT. CONCLUSION: The data suggest that cardioacceleration in chronic renal failure is caused by a diminished cardiac parasympathetic tone in the presence of a functionally intact intrinsic cardiac cholinergic signalling system.

• MeSH
• atropin farmakologie   MeSH
• beta blokátory farmakologie   MeSH
• cholin-O-acetyltransferasa genetika   metabolismus   MeSH
• karbachol farmakologie   MeSH
• kardiotonika farmakologie   MeSH
• krysa rodu rattus MeSH
• ledviny chirurgie   metabolismus   účinky léků   MeSH
• messenger RNA genetika   metabolismus   MeSH
• metipranolol farmakologie   MeSH
• nefrektomie MeSH
• nervus vagus fyziologie   účinky léků   MeSH
• noradrenalin metabolismus   MeSH
• parasympatický nervový systém fyziologie   účinky léků   MeSH
• parasympatolytika farmakologie   MeSH
• polymerázová řetězová reakce s reverzní transkripcí MeSH
• potkani Wistar MeSH
• proteiny nervové tkáně genetika   metabolismus   MeSH
• proteiny přenášející neurotransmitery přes plazmatickou membránu genetika   metabolismus   MeSH
• srdce inervace   MeSH
• srdeční frekvence fyziologie   MeSH
• vezikulární transportní proteiny acetylcholinu genetika   metabolismus   MeSH
• western blotting MeSH
• zvířata MeSH
• Check Tag
• krysa rodu rattus MeSH
• mužské pohlaví MeSH
• zvířata MeSH
• Publikační typ
• práce podpořená grantem MeSH