NADPH- diaphorase positive cardiac neurons in the atria of mice. A morphoquantitative study (original) (raw)
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Morphologic pattern of the intrinsic ganglionated nerve plexus in mouse heart
Heart Rhythm, 2011
BACKGROUND-Both normal and genetically modified mice are excellent models to investigate molecular mechanisms of arrhythmogenic cardiac diseases that may associate with an imbalance between the sympathetic and the parasympathetic nervous input to the heart. OBJECTIVE-We sought to: (1) determine the structural organization of the mouse cardiac neural plexus; (2) identify extrinsic neural sources and their relationship with the cardiac plexus; and (3) reveal any anatomical differences in the cardiac plexus between mouse and other species.
Regional distribution and extrinsic innervation of intrinsic cardiac neurons in the guinea pig
The Journal of Comparative Neurology, 1999
Mammalian intrinsic cardiac neurons subserve different functions in different cardiac regions, but the regional anatomical organisation of the intracardiac nervous system is not well understood. We investigated the quantitative and qualitative distribution of cholinergic and adrenergic elements, and the intracardiac pathways of extrinsic cardiac nerves, in whole-mount preparations of guinea pig atria. Protein gene product 9.5 immunoreactivity (PGP 9.5-IR) marked intracardiac neuronal elements; immunoreactions for choline acetyltransferase (ChAT-IR) and tyrosine hydroxylase (TH-IR) distinguished cholinergic and adrenergic components, respectively. Catecholamine-containing components were identified by aldehydeinduced fluorescence histochemistry. Mean total number of atrial neurons was 1510 Ϯ 251 (SE); 85% of these occurred in ganglia of Յ 20 neurons. All neuronal somata expressing PGP 9.5-IR also expressed ChAT-IR, suggesting that these neurons were cholinergic. Right (RA) and left (LA) atria had statistically similar neuronal densities (6.4 Ϯ 1.2 and 2.4 Ϯ 0.7 neurons/mm 2 , respectively; analysis of variance, PՅ0.05). Neurons in RA were concentrated intercavally; LA neurons were concentrated near pulmonary vein ostia. Greatest density occurred in the interatrial septum (16.3 Ϯ 4.0 neurons/mm 2 ). No neuronal somata expressed TH-IR or contained detectable amines but these elements were expressed by somata of small cells (mean total 124 Ϯ 33) throughout the atria, primarily associated with ganglia. Amineand TH-containing varicosities were also present in ganglia, representing potential sites for adrenergic modulation of ganglionic neurotransmission. Branches of extrinsic cardiopulmonary and vagus nerves were distributed to all parts of both atria. The organisation of the intracardiac nervous system revealed in this study will facilitate further investigations of regional autonomic control of the heart.
Heart Rhythm, 2011
BACKGROUND-The intrinsic neural plexus of the mouse heart has not been adequately investigated despite the extensive use of this species in experimental cardiology. OBJECTIVE-We determined the distribution of cholinergic, adrenergic and sensory neural components in whole-mount mouse heart preparations using double immunohistochemical labeling. METHODS AND RESULTS-Intrinsic neurons were concentrated within 19±3 ganglia (n = 20 mice) of varying size, scattered on the medial side of the inferior caval (caudal) vein on the right atrium and close to the pulmonary veins on the left atrium. Of a total of 1082±160 neurons, most somata (83%) were choline acetyltransferase (ChAT)-immunoreactive, while 4% were tyrosine hydroxylase (TH)-immunoreactive; 14% of ganglionic cells were biphenotypic for ChAT and TH. The most intense ChAT staining was observed in axonal varicosities. ChAT was evident in nerve fibers interconnecting intrinsic ganglia. Both ChAT and TH immunoreactivity were abundant within the nerves accessing the heart. However, epicardial TH-immunoreactive nerve fibers were predominant on the dorsal and ventral left atrium, whereas most ChAT-positive axons proceeded on the heart base toward the large intrinsic ganglia and on the epicardium of the root of the right cranial vein. Substance P-positive and calcitonin gene-related peptide-immunoreactive nerve fibers were abundant on the epicardium and within ganglia adjacent to the heart hilum. Small intensely fluorescent cells were grouped into clusters of 3-8 and dispersed within large ganglia or separately on the atrial and ventricular walls. CONCLUSIONS-While some nerves and neuronal bundles of the mouse epicardial plexus are mixed, most express either adrenergic or cholinergic markers. Therefore, selective stimulation and/or ablation of the functionally distinct intrinsic neural pathways should allow the study of specific effects on cardiac function.
Synapse, 1997
The pattern of association between neurotensin (NT)-immunoreactive (NTIR) preganglionic nerve terminals and cardiac and noncardiac neurons in the stellate ganglion of the cat is analyzed, based on the finding of an excitatory modulation effect of exogenous NT on cardiac functions. For this purpose, NT-containing terminals were labeled by immunohistochemistry, and ganglion cells were detected by retrograde labeling of cardiac and vertebral nerves to identify cardiac and noncardiac neurons. To determine a possible regional localization of NTIR terminals and ganglion cells, the ganglia were divided into four areas: caudal, dorsomedial, cranial, and ventromedial, related to the two major afferent nerves (thoracic white rami 3 [T3WR] and 2 [T2WR]) and the two efferent nerves (vertebral and cardiac). NTIR terminals were widespread in the complete ganglion tissue; they covered practically all the regions explored, although two clusters of high concentration of NTIR terminals were detected in the cranial and caudal areas. By retrograde labelling it was found that cardiac cells were arranged around the exit of the cardiac nerve and that the vertebral neurons were extended from the exit of the vertebral nerve to the entrance of T3WR. The finding of association of NTIR terminals with cardiac neurons may account for the cardioregulatory effect of NT; however, since the presence of NTIR terminals close to the noncardiac neurons is notorious, other regulatory functions of NT must be considered.
2003
The study was designed to determine the three-dimensional organization of the rat intrinsic cardiac neural plexus (ICNP) and to ascertain whether the rat heart undergoes a decrease in neuronal number with aging as has been reported for other mammalian species, including human. Juvenile (3-4 weeks of age, n = 14) and adult (more than 2 months of age, n = 23) animals were examined using enzyme histochemistry for acetylcholinesterase in order to visualize the ICNP in total hearts. The number of intrinsic cardiac neurons was estimated by counting nerve cells in serial sections of the atrial pieces stained with cresyl fast violet. The total number of intrinsic cardiac neurons in old rats was 6576 -317. The juvenile animals contained significantly fewer such neurons, only 5009 -332. Approximately 70% of all intracardiac neurons were amassed within the heart hilum, while 30% of the neurons were distributed epicardially. Within the interatrial septum, only 11 -11 neurons were identified in the juvenile and 6 -4 neurons in old rats. Extrinsic nerves entered the rat heart in both the arterial and venous parts of the cardiac hilum. The nerves from the arterial part of the cardiac hilum extended directly to the ventricles but the nerves from the venous part of the hilum formed a particular nerve plexus of the cardiac hilum on the heart base. Within the rat epicardium, intrinsic nerves clustered into six routes by which they selectively projected to different atrial and/or ventricular regions. In conclusion, this study provides a detailed description of the three-dimen-sional organization of the rat ICNP and contradicts the decrease in neuronal number with aging in the rat heart.
Morphological study of cultured cardiac ganglionic neurons from different postnatal stages of rats
Autonomic Neuroscience, 2000
This study sought to establish a culture model of cardiac ganglia (CG) neurons of the Sprague-Dawley (SD) rat which could by used to study the distinct characteristics of CG neurons. After culturing, the morphology and immunocytochemistry of CG neurons obtained on different days after birth were compared. Samples of CG neurons were taken from the posterior atrial wall of rats aged 7, 14, 21 and 40 postnatal days (designated as P7, P14, P21 and P40, respectively). During 3-6 days of culture, the morphological changes of the cultured neurons were monitored using a light microscope. Immunocytochemical staining of the neurofilaments (NF-L, -M and -H) was performed to identify the CG neurons and the changes in morphology. The differences in size of the CG soma of each culture were compared by morphometry. Frozen sections of CG neurons were used as the in vivo control of the above experiments. The results showed that the rate of growth in size of the CG soma was highest in the P7 group, and was slower after weaning (21 days after birth). Cultured neurons were categorized into unipolar-like (Type I), multipolar-like (Type II), and bipolar-like (Type III) based on their morphological characteristics. In NF immuocytochemical staining, there were strong responses to NF-H and NF-M in all cultures, but not to NF-L. More specifically, responses to NF-H were mainly observed in perikaryons and neurites, whereas the responses to NF-M were mainly in perikaryons. The present study has established a culture system for cardiac ganglia neurons of SD rats. Our results show that the intracardiac neurons were still developing in their somata and the processes and that various responses to different antibodies of NF for CG neurons occurred in different postnatal stages in rats.
Journal of Anatomy, 2014
Although the rabbit is routinely used as the animal model of choice to investigate cardiac electrophysiology, the neuroanatomy of the rabbit heart is not well documented. The aim of this study was to examine the topography of the intrinsic nerve plexus located on the rabbit heart surface and interatrial septum stained histochemically for acetylcholinesterase using pressure-distended whole hearts and whole-mount preparations from 33 Californian rabbits. Mediastinal cardiac nerves entered the venous part of the heart along the root of the right cranial vein (superior caval vein) and at the bifurcation of the pulmonary trunk. The accessing nerves of the venous part of the heart passed into the nerve plexus of heart hilum at the heart base. Nerves approaching the heart extended epicardially and innervated the atria, interatrial septum and ventricles by five nerve subplexuses, i.e. left and middle dorsal, dorsal right atrial, ventral right and left atrial subplexuses. Numerous nerves accessed the arterial part of the arterial part of the heart hilum between the aorta and pulmonary trunk, and distributed onto ventricles by the left and right coronary subplexuses. Clusters of intrinsic cardiac neurons were concentrated at the heart base at the roots of pulmonary veins with some positioned on the infundibulum. The mean number of intrinsic neurons in the rabbit heart is not significantly affected by aging: 2200 AE 262 (range 1517-2788; aged) vs. 2118 AE 108 (range 1513-2822; juvenile). In conclusion, despite anatomic differences in the distribution of intrinsic cardiac neurons and the presence of well-developed nerve plexus within the heart hilum, the topography of all seven subplexuses of the intrinsic nerve plexus in rabbit heart corresponds rather well to other mammalian species, including humans.
The Anatomical record, 1970
Differences in succinate dehydrogenase and cytochrome oxidase activity and also in the Qoe for a medium containing pyruvate, glutamate, fumarate and glucose (equimolar) were found using histochemical and manometrical methods, when muscle cells of the atria and the ventricles in the guinea pig heart were compared. Most of the activity values were higher in the ventricles than in the atria. According to cytomorphometric measurements, these differences can be explained by differences in the mitochondrial volume (per unit volume of cytoplasm) rather than by a different ultrastructural organization of the individual mitochondria, since they show the same stereological organization in both the atria and the ventricles. The reduced mitochondrial volume in the atria results in a lower density of "oxidative" (i.e., inner mitochondrial) membranes per unit volume of cytoplasm.
Distribution and Number of Intracardiac Ganglion Cells in the Rat
The purpose of this study was to reevaluate the distribution and the number of intracardiac ganglion cells in the rat. Hearts were excised from adult male Wistar rats. The distribution of the ganglia was mapped using thick, frozen sections of rat heart histochemically stained for acetylcholinesterase. The ganglion cells were divided into several groups with the largest group located dorsal to the inferior interatrial septum. The disector method was used to estimate the number of neurons in seven micron thick paraffin sections. The number of neurons in the rat heart was 3629±337 (mean ±S.E., n=3).
Morphological Studies of Cardiac Ganglionic Neurons in Primary Cell Culture
1994
Wann-Yee Her, Mei-Fang Yang, Tin-Hsin Hsiao and Keh-Min Liu (1994) Morphological studies of cardiac ganglionic neurons in primary cell culture. Zoological Studies 33(2): 108-113. In mammals, several groups of cardiac ganglia (CG) are sparsely distributed in the posterior wall of the atrium and the interatrial septum. The CG from early postnatal rats were cultured for optimum observation of cellular morphology and direct ac cess to neurons for immunohistochemical analysis. During the two weeks observation period, CG neurons were immunocytochemically stained with neuron-specific enolase (NSE) or calcitonin gene-related peptide (CGRP). Results showed that one day after cultivation cells migrated out from the cultured cells mass. After 4 days of culture, isolated or aggregated neurons dispersed on the flattened fibroblasts layer. Most neurons are multipolar and contain an eccentric oval nucleus. Two neuron types were observed, type I neurons, characterized by a few, short cytoplasmic p...