RESUMO
This study was conducted to test the hypothesis that the pulmonary artery is involved in neural respiratory control and to identify the involved topographical region, if any. Six adult rabbits were anesthetized, artificially ventilated, and the chest was opened. The outer surface of the extra-pulmonary portion of the pulmonary artery was electrically stimulated by monitoring phrenic nerve activity. Phrenic nerve activity increased in three of the six rabbits when the proximal dorsal surface of the pulmonary trunk was stimulated. This positive response was abolished after bilateral vagotomy. In histological examinations we found densely grouped cells, i.e. pulmonary glomic tissue, with a fine nerve bundle in the tissue adjacent to the dorsal surface of the pulmonary trunk where electrical stimulation elicited respiratory augmentation. We suggest that there is a neural substrate which is involved in respiratory control inside the wall of or in the region adjacent to the proximal dorsal surface of the pulmonary trunk. Further studies to anatomically identify the neural substrate and clarify its physiological role in respiratory control are necessary.
Assuntos
Nervo Frênico/fisiologia , Artéria Pulmonar/anatomia & histologia , Artéria Pulmonar/fisiologia , Mecânica Respiratória/fisiologia , Animais , Corpos Aórticos/anatomia & histologia , Corpos Aórticos/fisiologia , Fenômenos Fisiológicos Cardiovasculares , Estimulação Elétrica , Feminino , Artéria Pulmonar/inervação , Coelhos , Vagotomia , Nervo Vago/fisiologiaAssuntos
Corpos Aórticos/fisiologia , Células Quimiorreceptoras/fisiologia , Reflexo/fisiologia , Almitrina/farmacologia , Anestesia , Animais , Corpos Aórticos/anatomia & histologia , Corpos Aórticos/efeitos dos fármacos , Biguanidas/farmacologia , Pressão Sanguínea/efeitos dos fármacos , Células Quimiorreceptoras/anatomia & histologia , Células Quimiorreceptoras/efeitos dos fármacos , Eletrofisiologia , Frequência Cardíaca/efeitos dos fármacos , Masculino , Nervo Frênico/efeitos dos fármacos , Nervo Frênico/fisiologia , Ratos , Ratos Sprague-Dawley , Reflexo/efeitos dos fármacos , Respiração/efeitos dos fármacosRESUMO
The dorsal vagal complex in the medulla oblongata is the hub of the central nervous system network that produces vagal cephalic-phase reflexes. The preganglionic motor neurons controlling these cephalic responses of digestion and metabolism are organized topographically in longitudinal columnar subnuclei in the dorsal motor nucleus of the vagus. Gustatory and other visceral afferent inputs project into different subnuclei of the nucleus of the solitary tract capping the dorsal motor nucleus. Descending projections from more rostral stations of the neuroaxis project to the nuclei of the dorsal vagal complex, providing input both from exteroceptive senses, such as olfaction and vision, and from forebrain areas that modulate reflex strength. Recent structural analyses of the dorsal vagal complex, as well as characterizations of the region's inputs and neurochemistry, have provided a more complete understanding of the neural basis of cephalic-phase responses.
Assuntos
Corpos Aórticos/anatomia & histologia , Ingestão de Alimentos/fisiologia , Núcleo Solitário/fisiologia , Nervo Vago/fisiologia , Corpos Aórticos/fisiologia , Digestão/fisiologia , Ingestão de Alimentos/psicologia , Alimentos , Humanos , Neurotransmissores/fisiologiaRESUMO
Um caso de corpúsculo aórtico pulmonar e canal arterial pérvio é descrito. A possível participação deste corpúsculo na oclusão do canal arterial, é discutida e apresentada. O corpúsculo aórtico pulmonar encontrado foi estudado do ponto de vista anatomopatológico e relacionado com o caso cirúrgico, que merece breve relato
Assuntos
Humanos , Recém-Nascido , Corpos Aórticos/anatomia & histologia , Corpos Aórticos/patologiaRESUMO
An inventory of the distribution of thoracic glomus tissue (thoracic chemoreceptor tissue, aortic bodies) has been derived from serial sections in foetal, newborn and adult rats. In contrast to other common experimental species, such as the cat and dog, aortic bodies are an inconstant feature and, on the whole, are scarce in the rat. These morphological findings correlate well with experimental studies, indicating an absence or paucity of thoracic chemoreceptor activity in the rat. The results are discussed in terms of their physiological and pathophysiological implications and a revised model of the peripheral arterial chemoreceptor system is presented.
Assuntos
Corpos Aórticos/anatomia & histologia , Células Quimiorreceptoras/anatomia & histologia , Paragânglios não Cromafins/anatomia & histologia , Ratos/anatomia & histologia , Animais , Animais Recém-Nascidos/anatomia & histologia , Corpos Aórticos/embriologia , Corpos Aórticos/patologia , Atrofia/veterinária , Gatos/anatomia & histologia , Cães/anatomia & histologia , Feminino , Hipertrofia/veterinária , Hipóxia/patologia , Hipóxia/veterinária , Masculino , Ratos Endogâmicos , Doenças dos Roedores/patologia , Nervo Vago/fisiologiaRESUMO
The chief cells of the aortic body (subclavian body) of adult New Zealand white rabbits were examined by ultrastructural stereological analysis. The chief cell nuclei occupy 26.5% of the total volume. Dense-core vesicles account for 16.5% of the cytoplasmic volume, followed by mitochondria (11.6%), endoplasmic reticulum (3.3%), and Golgi apparatus (0.6%). The dense-core vesicles measure approximately 131.6 nm in diameter (corrected) and exhibit a heterogeneous size distribution. Both perivascular adrenergic nerve terminals and presumptive afferent terminals presynaptic to the chief cells are observed. The mean synaptic vesicle size of the terminals adjacent to chief cells is 54 nm. The heterogeneous size distribution of the dense-core vesicles of chief cells may indicate the storage of different biogenic amines and/or different secretion or maturation states within the chief cells.
Assuntos
Corpos Aórticos/ultraestrutura , Paragânglios não Cromafins/ultraestrutura , Animais , Corpos Aórticos/anatomia & histologia , Terminações Nervosas/ultraestrutura , Organoides/ultraestrutura , Coelhos , Vesículas Sinápticas/ultraestruturaRESUMO
In the buffalo, the left aortic nerve ramifies in the periarterial connective tissue between the ventral surface of the aortic arch and the truncus pulmonalis. The right aortic nerve ramifies over the dorsal and right aspects of the aorta ascendens near its origin. The histograms of myelinated fibres of both left and right aortic nerve are distinctly unimodal with peak around 4-6 micron (64.2-67.8%). The left aortic body is situated in the periarterial connective tissue between the ventral surface of the aortic arch and the truncus pulmonalis, while the right aortic body is located in the tunica adventitia of the dorsal and right aspects of the aorta ascendens near its origin. The greatest sagittal section area of the left aortic body is 0.102 +/- 0.009 mm2 and that of the right aortic body is 0.041 +/- 0.002 mm2. The organ is highly vascular. The mean size of the glomus cells from the left aortic body is 7.68 +/- 0.9 micron x 9.37 +/- 0.13 micron (short diameter x long diameter), whereas the corresponding value for the right aortic body is 7.84 +/- 0.14 micron x 9.86 +/- 0.21 micron; and their density values are (11,417 +/- 301.7)/mm2 and (9,839 +/- 213.3)/mm2 respectively.