Lung inflation: effects on heart rate, respiration, and vagal afferent activity in seals

1981 ◽  
Vol 240 (2) ◽  
pp. H190-H198 ◽  
Author(s):  
J. E. Angell-James ◽  
R. Elsner ◽  
M. De Burgh Daly
Keyword(s):  
Transpulmonary Pressure ◽  
Harbor Seal ◽  
Nerve Fibers ◽  
Cardiac Response ◽  
Impulse Frequency ◽  
Lung Inflation ◽  
Afferent Nerve Fibers ◽  
Close Relationship ◽  
Vagal Afferent ◽  
Carotid Body Chemoreceptors

In the anesthetized harbor seal, Phoca vitulina, the Hering-Breuer inflation reflex was weak and comparable to that in humans. Single inflations of the lungs from a syringe during the expiratory phase of normal breathing caused temporary inhibition of breathing and an immediate tachycardia dependent on the integrity of the cervical vagosympathetic nerves. A similar cardiac response occurred when the lungs were artificially inflated during an experimental dive and under conditions in which apnea and bradycardia were reflexly induced by a combination of stimulation of the carotid body chemoreceptors and of the trigeminal or laryngeal input. Recordings from single vagal afferent nerve fibers innervating presumptive pulmonary stretch receptors showed a close relationship between the increase in impulse frequency and increase in lung volume or transpulmonary pressure. It appears that in diving the decrease in pulmonary stretch receptor activity during apnea, combined with cessation of central inspiratory neuronal drive, is an important integrative mechanism that helps development of the reflex bradycardia of trigeminal, carotid, chemoreceptor, and baroreceptor origin.

Effect of Volume and Rate of Inflation and Deflation on Transpulmonary Pressure and Response of Pulmonary Stretch Receptors

1956 ◽  
Vol 187 (3) ◽  
pp. 558-566 ◽  
Author(s):  
Harry L. Davis ◽  
Ward S. Fowler ◽  
Edward H. Lambert
Keyword(s):  
Lung Volume ◽  
Action Potentials ◽  
Work Of Breathing ◽  
Transpulmonary Pressure ◽  
Nerve Fibers ◽  
Discharge Frequency ◽  
Afferent Nerve Fibers ◽  
Stretch Receptors ◽  
Pulmonary Stretch Receptors ◽  
Vagal Afferent

Action potentials of single vagal afferent nerve fibers from slowly adapting pulmonary stretch receptors, transpulmonary pressure and rate of air flow were recorded in anesthetized cats with open thoraxes during varied volumes and rates of inflation and deflation of the lungs. Both discharge frequency and total transpulmonary pressure varied with lung volume and also with its rate and sign of change. Effects of acceleration of volume on discharge frequency were not observed. The receptors provide signals related to the work of breathing.

Cholinesterase activity in quail primary lymphoid organs

Biologia ◽  
2013 ◽  
Vol 68 (6) ◽  
Author(s):  
František Dorko ◽  
Jaroslav Horáček ◽  
Ján Tokarčík ◽  
Michal Miko
Keyword(s):  
Germinal Center ◽  
Cholinesterase Activity ◽  
Histochemical Study ◽  
Nerve Fibers ◽  
Lymphoid Organs ◽  
Bursa Of Fabricius ◽  
Lymphoid Follicles ◽  
Age Dependent ◽  
Close Relationship ◽  
Thymic Medulla

AbstractThe present histochemical study was carried out to analyze the distribution and topography of acetylcholinepositive nerve fibers in the thymus and bursa of Fabricius of quails. The AChE-positive nerve fibers were demonstrated by direct thiocholine histochemical method. Nerve fibers present in the thymuses form periarterial nerve plexuses located mostly in the interlobular septa and on the cortico-medullary junction. Vessels-independent nerve fibers occur also in the parenchyma of thymic medulla, but rarely in parenchyma of the cortex. Within the connective tissue between the bursa of Fabricius and the wall of proctodeum we observed conspicuous AChE-positive ganglia, often in close relationship to greater arteries. Within the wall of bursa of Fabricius, AChE-positive nerve fibers create nerve plexuses around arteries. We observed a close relationship between lymphoid follicules in bursal submucosa and mucosa and AChE-positive nerve fibers. Nerve fibers create a ring around lymphoid follicles, but do not penetrate into the germinal center of the follicle. Arteries inside quail thymuses and bursae of Fabricius contain rich AChE-positive nerve plexuses, when compared to the veins, which have a very poor presence of AChE-positive nerves. According to lesser presence and decreased density of AChE-positive nerve fibers in older animals, we described age-dependent changes in both quail primary lymphoid organs.

Morphological signs of neurogenic inflammation in the heart of rats during aging

2022 ◽  
pp. 831-840
Author(s):  
Е.И. Чумасов ◽  
Е.С. Петрова ◽  
Д.Э. Коржевский
Keyword(s):  
Neurogenic Inflammation ◽  
Plasma Cells ◽  
Nerve Fibers ◽  
Blood Capillaries ◽  
Pgp 9.5 ◽  
Sympathetic Nerve Fibers ◽  
Close Relationship ◽  
The Right ◽  
Inflammatory Infiltrates ◽  
Heart Apparatus

С помощью гистологических методов окраски толуидиновым синим, гематоксилином и эозином и иммуногистохимических реакций на белок PGP 9.5, тирозингидроксилазу (ТГ), белок Iba-1, изучены клеточные изменения в разных отделах сердца крыс линии Wistar в возрасте 18- 23 мес. В соединительной ткани основания сердца обнаружены очаговые воспалительные инфильтраты, внутри которых выявлены PGP 9.5 и ТГ сплетения, состоящие из парасимпатических и симпатических нервных волокон. В области клапанного аппарата, на границе фиброзного кольца и миокарда правого предсердия, обнаружены патологические изменения нервных структур - дегенерация нервных пучков и зернистый распад варикозных аксонов терминального сплетения. Установлены тесные взаимоотношения аксонов терминальной нервной сети с клетками воспалительных инфильтратов и кровеносными сосудами. Определены закономерности встречаемости в различных отделах миокарда у старых животных нейроклеточных воспалительных комплексов, состоящих из нервных волокон, кровеносных капилляров и клеток-участников местного воспалительного процесса (тучных клеток, макрофагов, фибробластов, плазмоцитов). Установлен хронический характер нейрогенного воспаления в сердце при старении. Using histological methods of staining with toluidine blue, hematoxylin-eosin and immunohistochemical reactions for the PGP 9,5 protein, tyrosine hydroxylase (TH), Iba-1 protein, cellular changes in different parts of the heart of Wistar rats at the age of 18-23 months were studied. In the connective tissue of the heart base, focal inflammatory infiltrates were found, near which PGP 9.5 and TH plexuses, consisting of parasympathetic and sympathetic nerve fibers, were detected. In the area of the valvular heart apparatus, at the border of the anneau fibreux and the myocardium of the right atrium, pathological changes in nerve structures were found: degeneration of nerve fibers and granular destruction varicose axons of the terminal plexus. A close relationship has been established between axons of the terminal nervous network and cells of inflammatory infiltrates and blood capillaries. The features of the localization of neurocellular inflammatory complexes consisting of nerve fibers, blood capillaries and cells participating in the local inflammatory process (mast cells, histiocytes, monocytes, fibroblasts, plasma cells) in various parts of the myocardium in old animals are described. The chronic nature of neurogenic inflammation in the heart during aging has been established.

Spontaneous action potential generation due to persistent sodium channel currents in simulated carotid body afferent fibers

2008 ◽  
Vol 104 (5) ◽  
pp. 1394-1401 ◽  
Author(s):  
David F. Donnelly
Keyword(s):  
Carotid Body ◽  
High Sensitivity ◽  
Nerve Fibers ◽  
Afferent Nerve ◽  
Random Pattern ◽  
Nerve Terminals ◽  
Discharge Rates ◽  
Afferent Nerve Fibers ◽  
Axonal Diameter ◽  
Spontaneous Action

The mechanism by which action potentials (APs) are generated in afferent nerve fibers in the carotid body is unknown, but it is generally speculated to be release of an excitatory transmitter and synaptic depolarizing events. However, previous results suggested that Na+ channels in the afferent nerve fibers play an important role in this process. To better understand the potential mechanism by which Na+ channels may generate APs, a mathematical model of chemoreceptor nerve fibers that incorporated Hodgkin-Huxley-type Na+ channels with kinetics of activation and inactivation, as determined previously from recordings of petrosal chemoreceptor neurons, was constructed. While the density of Na+ channels was kept constant, spontaneous APs arose in nerve terminals as the axonal diameter was reduced to that in rat carotid body. AP excitability and pattern were similar to those observed in chemoreceptor recordings: 1) a random pattern at low- and high-frequency discharge rates, 2) a high sensitivity to reductions in extracellular Na+ concentration, and 3) a variation in excitability that increased with AP generation rate. Taken together, the results suggest that an endogenous process in chemoreceptor nerve terminals may underlie AP generation, a process independent of synaptic depolarizing events.

Effect of lung inflation on lung blood volume and pulmonary venous flow

1985 ◽  
Vol 58 (3) ◽  
pp. 954-963 ◽  
Author(s):  
R. Brower ◽  
R. A. Wise ◽  
C. Hassapoyannes ◽  
B. Bromberger-Barnea ◽  
S. Permutt
Keyword(s):  
Blood Volume ◽  
Transpulmonary Pressure ◽  
Left Ventricular ◽  
Respiratory Cycle ◽  
Pulmonary Vasculature ◽  
Venous Flow ◽  
Lung Inflation ◽  
Pulmonary Venous Flow ◽  
Respiratory Wave ◽  
Left Ventricular Preload

Phasic changes in lung blood volume (LBV) during the respiratory cycle may play an important role in the genesis of the respiratory wave in arterial pressure, or pulsus paradoxus. To better understand the effects of lung inflation on LBV, we studied the effect of changes in transpulmonary pressure (delta Ptp) on pulmonary venous flow (Qv) in eight isolated canine lungs with constant inflow. Inflation when the zone 2 condition was predominant resulted in transient decreases in Qv associated with increases in LBV. In contrast, inflation when the zone 3 condition was predominant resulted in transient increases in Qv associated with decreases in LBV. These findings are consistent with a model of the pulmonary vasculature that consists of alveolar and extra-alveolar vessels. Blood may be expelled from alveolar vessels but is retained in extra-alveolar vessels with each inflation. The net effect on LBV and thus on Qv is dependent on the zone conditions that predominate during inflation, with alveolar or extra-alveolar effects being greater when the zone 3 or zone 2 conditions predominate, respectively. Lung inflation may therefore result in either transiently augmented or diminished Qv. Phasic changes in left ventricular preload may therefore depend on the zone conditions of the lungs during the respiratory cycle. This may be an important modulator of respiratory variations in cardiac output and blood pressure.

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