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Heart Atria (heart + atrium)
Selected AbstractsIdentification of ,- and ,-opioid receptors as potential targets to regulate parasympathetic, sympathetic, and sensory neurons within rat intracardiac gangliaTHE JOURNAL OF COMPARATIVE NEUROLOGY, Issue 18 2010Shaaban A. Mousa Abstract Recent interest has been focused on the opioid regulation of heart performance; however, specific allocation of opioid receptors to the parasympathetic, sympathetic, and sensory innervations of the heart is scarce. Therefore, the present study aimed to characterize such specific target sites for opioids in intracardiac ganglia, which act as a complex network for the integration of the heart's neuronal in- and output. Tissue samples from rat heart atria were subjected to RT-PCR, Western blot, radioligand-binding, and double immunofluorescence confocal analysis of , (M)- and , (K)-opioid receptors (ORs) with the neuronal markers vesicular acetylcholine transporter (VAChT), tyrosine hydroxylase (TH), calcitonin gene-related peptide (CGRP), and substance P (SP). Our results demonstrated MOR- and KOR-specific mRNA, receptor protein, and selective membrane ligand binding. By using immunofluorescence confocal microscopy, MOR and KOR immunoreactivity were colocalized with VAChT in large-diameter parasympathetic principal neurons, with TH-immunoreactive small intensely fluorescent (SIF) cells, and on nearby TH-IR varicose terminals. In addition, MOR and KOR immunoreactivity were identified on CGRP- and SP-IR sensory neurons throughout intracardiac ganglia and atrial myocardium. Our findings show that MOR and KOR are expressed as mRNA and translated into specific receptor proteins on cardiac parasympathetic, sympathetic, and sensory neurons as potential binding sites for opioids. Thus, they may well play a role within the complex network for the integration of the heart's neuronal in- and output. J. Comp. Neurol. 518:3836,3847, 2010. © 2010 Wiley-Liss, Inc. [source] Manganese alters mitochodrial integrity in the hearts of swine marginally deficient in magnesium,BIOFACTORS, Issue 2 2004Kevin B. Miller Abstract It was previously reported that pigs marginally deficient in magnesium (Mg) and fed diets high in manganese (Mn) died suddenly with signs of sudden cardiac death. Manganese, which has properties similar to Mg, may exacerbate Mg-deficiency and be accumulated by mitochondria resulting in ultrastructural damage. The objective of this study was to determine whether deaths of the type previously observed were mediated by adverse interactions of Mn and Mg resulting in ultrastructural damage to the myocardium, alterations in electrocardiographic recordings and tissue retention of Mn, Mg and calcium (Ca). Forty-eight pigs were fed one of six diets in a 2 × 3 factorial arrangement of Mg (100 or 1000 mg Mg/kg) and Mn (5, 50 or 500 mg Mn/kg) for 8 weeks. Left ventricle muscle samples were collected for examination by transmission electron microscopy. No differences in heart muscle ultrastructure were observed between pigs fed low and adequate dietary Mg. However, marked myocardial necrosis and mitochondrial swelling were observed in pigs fed high dietary Mn when combined with low Mg. Feeding low dietary Mg elevated minimum (P < 0.01), maximum (P < 0.05) and average (P < 0.001) heart rates. Low dietary Mg resulted in a 55% probability of a ventricular beat being recorded (P = 0.05) and lower Mg (P < 0.02) and Ca (P < 0.04) contents in heart atria and ventricles. These results suggest that high Mn, when fed in combination with low Mg, disrupts mitochondrial ultrastructure and is associated with the sudden deaths previously reported. [source] Tissue tropism of nervous necrosis virus (NNV) in Atlantic cod, Gadus morhua L., after intraperitoneal challenge with a virus isolate from diseased Atlantic halibut, Hippoglossus hippoglossus (L.)JOURNAL OF FISH DISEASES, Issue 8 2009K Korsnes Abstract Atlantic cod, Gadus morhua, averaging 100 g, were experimentally challenged by intraperitoneal injection of nervous necrosis virus (NNV) originating from Atlantic halibut. Cod tissues, including blood, gill, pectoral fin, barbel, ventricle, atrium, spleen, liver, lateral line (including muscle tissue), eye (retina) and brain, were sampled at day 25 and 130 and investigated by real-time RT-PCR for the presence of NNV. Relative quantifications at day 130 were calculated using the 2,,,Ct method. Immunosuppression by injection of prednisolone-acetate was introduced for a 30-day period, and tissue sampled at day 180 and relative quantification estimated. No mortality or clinical signs of disease were observed in the challenged group. The challenge resulted in detection of NNV in blood, spleen, kidney, liver, heart atrium and heart ventricle at day 25, and by the end of the experiment NNV showed a clear increase in brain and retina, suggesting these to be the primary tissues for viral replication. There was no increase in the relative amount of NNV in blood, atrium, ventricle, spleen, liver and kidney. Corticosteroid implants resulted in a weak increase in virus RNA in spleen, kidney, liver and brain. These findings suggest that Atlantic cod is susceptible to infection with NNV from halibut. The observed tissue tropism patterns suggest an initial viraemic phase, followed by neurotrophy. Head-kidney is the best tissue identified for possible NNV detection by non-lethal biopsy, but detection was not possible in all injected fish. [source] Structural and Histochemical Studies on the Teleostean Bulbus ArteriosusANATOMIA, HISTOLOGIA, EMBRYOLOGIA, Issue 6 2009I. L. Leknes Summary The structure and histochemical properties of the bulbus arteriosus in two species from an evolutionary old teleost family, Characidae, and in three modern teleosts, family Cichlidae, are described. The bulbar wall was composed of an outer layer, a middle layer and a strongly folded inner layer covered by a thick, granule-rich endothelial cell layer towards the lumen. One of the cichlid species (Thorichthys meeki) was injected intraperitoneally with horse ferritin; the endothelial cell layer of the heart atrium and ventricle displayed high ability to endocytose ferritin particles from the blood stream, but the corresponding layer in the bulbus arteriosus displayed no such uptake. This finding suggests that the bulbar endothelial cell layer plays no scavenger or immunological blood cleansing roles in this species. The bulbar endothelial cell granules were strongly coloured by periodic acid,Schiff (PAS) in the present cichlids, but weakly coloured by PAS in the present characids. These cell layers were uncoloured by alkaline carmine in ethanol in both cichlids and characids. The negative carmine test combined with a positive PAS test for the bulbar endothelial cell layer in the present cichlids indicates that these cells contain only small amounts of polysaccharides. The weak PAS-colouring for the bulbar endothelial cell layer in characids indicates a very low content of sugars in these cells. These findings together with the fact that this cell layer in the present cichlids and characids was nearly uncoloured when treated with orcein, Heidenhain's Azan or Schmorl's solutions for elastic materials suggest that the bulbar endothelial granules do not play any role in the blood cleansing or in the rebuilding or maintenance of the ground substance or elastic material in the bulbar wall. Probably, the granules in the bulbar endothelial cell layer in the present species contain mainly proteins, connected to some PAS-positive polysaccharides to enhance their solubility. [source] | ||||||||||