Central Control of the Cardiovascular and Respiratory Systems and Their Interactions in Vertebrates

1999 ◽  
Vol 79 (3) ◽  
pp. 855-916 ◽  
Author(s):  
Edwin W. Taylor ◽  
David Jordan ◽  
John H. Coote
Keyword(s):  
Respiratory Rhythm ◽  
Nucleus Ambiguus ◽  
Motor Nucleus ◽  
Cardiorespiratory System ◽  
Preganglionic Neurons ◽  
Larval Amphibians ◽  
Dorsal Motor Nucleus ◽  
Changing Roles ◽  
Productive Research ◽  
And Control

This review explores the fundamental neuranatomical and functional bases for integration of the respiratory and cardiovascular systems in vertebrates and traces their evolution through the vertebrate groups, from primarily water-breathing fish and larval amphibians to facultative air-breathers such as lungfish and some adult amphibians and finally obligate air-breathers among the reptiles, birds, and mammals. A comparative account of respiratory rhythm generation leads to consideration of the changing roles in cardiorespiratory integration for central and peripheral chemoreceptors and mechanoreceptors and their central projections. We review evidence of a developing role in the control of cardiorespiratory interactions for the partial relocation from the dorsal motor nucleus of the vagus into the nucleus ambiguus of vagal preganglionic neurons, and in particular those innervating the heart, and for the existence of a functional topography of specific groups of sympathetic preganglionic neurons in the spinal cord. Finally, we consider the mechanisms generating temporal modulation of heart rate, vasomotor tone, and control of the airways in mammals; cardiorespiratory synchrony in fish; and integration of the cardiorespiratory system during intermittent breathing in amphibians, reptiles, and diving birds. Concluding comments suggest areas for further productive research.

scholarly journals Postnatal developmental expressions of neurotransmitters and receptors in various brain stem nuclei of rats

2005 ◽  
Vol 98 (4) ◽  
pp. 1442-1457 ◽  
Author(s):  
Qiuli Liu ◽  
Margaret T. T. Wong-Riley
Keyword(s):  
Brain Stem ◽  
Respiratory Control ◽  
Nucleus Ambiguus ◽  
Hypoglossal Nucleus ◽  
Motor Nucleus ◽  
Developmental Trend ◽  
Receptor Subunit ◽  
Cuneate Nucleus ◽  
Glycine Receptors ◽  
Dorsal Motor Nucleus

Previously, we reported that the expression of cytochrome oxidase in a number of brain stem nuclei exhibited a plateau or reduction at postnatal day (P) 3–4 and a dramatic decrease at P12, against a general increase with age. The present study examined the expression of glutamate, N-methyl-d-aspartate receptor subunit 1 (NMDAR1), GABA, GABAB receptors, glycine receptors, and glutamate receptor subunit 2 (GluR2) in the ventrolateral subnucleus of the solitary tract nucleus, nucleus ambiguus, hypoglossal nucleus, medial accessory olivary nucleus, dorsal motor nucleus of the vagus, and cuneate nucleus, from P2 to P21 in rats. Results showed that 1) the expression of glutamate increased with age in a majority of the nuclei, whereas that of NMDAR1 showed heterogeneity among the nuclei; 2) GABA and GABAB expressions decreased with age, whereas that of glycine receptors increased with age; 3) GluR2 showed two peaks, at P3–4 and P12; and 4) glutamate and NMDAR1 showed a significant reduction, whereas GABA, GABAB receptors, glycine receptors, and GluR2 exhibited a concomitant increase at P12. These features were present but less pronounced in hypoglossal nucleus and dorsal motor nucleus of the vagus and were absent in the cuneate nucleus. These data suggest that brain stem nuclei, directly or indirectly related to respiratory control, share a common developmental trend with the pre-Bötzinger complex in having a transient period of imbalance between inhibitory and excitatory drives at P12. During this critical period, the respiratory system may be more vulnerable to excessive exogenous stressors.

Distribution of vagal cardioinhibitory neurons in the medulla of the cat

1980 ◽  
Vol 238 (1) ◽  
pp. R57-R64 ◽  
Author(s):  
J. Ciriello ◽  
F. R. Calaresu
Keyword(s):  
Nucleus Tractus Solitarius ◽  
Border Region ◽  
Nucleus Ambiguus ◽  
Motor Nucleus ◽  
Dorsal Motor Nucleus ◽  
Antidromic Stimulation ◽  
Low Threshold ◽  
Vagal Bradycardia ◽  
Medullary Nuclei ◽  
Stimulation Of

Experiments were done in cats anesthetized with chloralose, paralyzed and artificially ventilated cats to obtain electrophysiological evidence on the medullary site of origin of vagal cardioinhibitory fibers. The regions of the nucleus ambiguus (AMB), dorsal motor nucleus of the vagus (DMV), nucleus tractus solitarius (NTS), and external cuneate nucleus (ECN) were systematically explored for units responding both to antidromic stimulation of the cardiac branches of the vagus (CBV) and to orthodromic stimulation of the carotid sinus and aortic depressor nerves. Eighty-six single units conforming to these criteria were found in the medulla: 30 in the AMB, 26 in the DMV, 12 in the NTS, 8 in the NTS-DMV border region, and 10 in the ECN. Antidromically evoked spikes had durations of 0.5--2.5 ms and followed stimulation frequencies of 20--500 Hz. The axons of these units conducted at velocities of 3.3--20.8 m/s. The specificity of activation of medullary units by cardioinhibitory fibers was tested in 11 units, which were found to respond consistently with an antidromic spike to stimulation of CBV but not to stimulation of the thoracic vagus. In eight spinal animals low threshold (less than 15 microA) sites eliciting vagal bradycardia were found in the same medullary nuclei where cardioinhibitory units had been located. These results indicate that vagal cardioinhibitory axons, originate in at least three medullary nuclei, the AMB, DMV, and NTS. Unit activity from the ECN may have been recorded from carioinhibitory fibers because of the short duration of the spike potentials.

Differential control over postganglionic neurons in rat cardiac ganglia by NA and DmnX neurons: anatomical evidence

2004 ◽  
Vol 286 (4) ◽  
pp. R625-R633 ◽  
Author(s):  
Zixi (Jack) Cheng ◽  
Hong Zhang ◽  
Shang Z. Guo ◽  
Robert Wurster ◽  
David Gozal
Keyword(s):  
Brain Stem ◽  
Motor Neurons ◽  
Nucleus Ambiguus ◽  
Motor Nucleus ◽  
Sprague Dawley ◽  
Tracer Injection ◽  
Cardiac Ganglia ◽  
Dorsal Motor Nucleus ◽  
Differential Control ◽  
The Brain

In previous single-labeling experiments, we showed that neurons in the nucleus ambiguus (NA) and the dorsal motor nucleus of the vagus (DmnX) project to intrinsic cardiac ganglia. Neurons in these two motor nuclei differ significantly in the size of their projection fields, axon caliber, and endings in cardiac ganglia. These differences in NA and DmnX axon cardiac projections raise the question as to whether they target the same, distinct, or overlapping populations of cardiac principal neurons. To address this issue, we examined vagal terminals in cardiac ganglia and tracer injection sites in the brain stem using two different anterograde tracers {1,1′-dioleyl-3,3,3′,3′-tetramethylindocarbocyanine methanesulfonate and 4-[4-(dihexadecylamino)-styryl]- N-methylpyridinium iodide} and confocal microscopy in male Sprague-Dawley rats. We found that 1) NA and DmnX neurons innervate the same cardiac ganglia, but these axons target separate subpopulations of principal neurons and 2) axons arising from neurons in the NA and DmnX in the contralateral sides of the brain stem enter the cardiac ganglionic plexus through separate bundles and preferentially innervate principal neurons near their entry regions, providing topographic mapping of vagal motor neurons in left and right brain stem vagal nuclei. Because the NA and DmnX project to distinct populations of cardiac principal neurons, we propose that they may play different roles in controlling cardiac function.

Electrophysiological study on the effects of leptin in rat dorsal motor nucleus of the vagus

2007 ◽  
Vol 292 (6) ◽  
pp. R2136-R2143 ◽  
Author(s):  
Tzu-Ling Li ◽  
Lih-Chu Chiou ◽  
You Shuei Lin ◽  
Jing-Ru Hsieh ◽  
Ling-Ling Hwang
Keyword(s):  
Potassium Conductance ◽  
Reversal Potential ◽  
Negative Slope ◽  
Motor Nucleus ◽  
Neonatal Rats ◽  
Patch Clamp Recording ◽  
Central Target ◽  
Preganglionic Neurons ◽  
Dorsal Motor Nucleus ◽  
Outward Currents

Immunoreactivity of leptin receptor (Ob-R) has been detected in rat dorsal motor nucleus of the vagus (DMNV). Here, we confirmed the presence of Ob-R immunoreactivity on retrograde-labeled parasympathetic preganglionic neurons in the DMNV of neonatal rats. The present study investigated the effects of leptin on DMNV neurons, including parasympathetic preganglionic neurons, by using whole cell patch-clamp recording technique in brain stem slices of neonatal rats. Leptin (30–300 nM) induced membrane depolarization and hyperpolarization, respectively, in 14 and 15 out of 80 DMNV neurons tested. Both leptin-induced inward and outward currents persisted in the presence of TTX, indicating that leptin affected DNMV neurons postsynaptically. The current-voltage (I–V) curve of leptin-induced inward currents is characterized by negative slope conductance and has an average reversal potential of −90 ± 3 mV. The reversal potential of the leptin-induced inward current was shifted to a more positive potential level in a high-potassium medium. These results indicate that a decrease in potassium conductance is likely the main ionic mechanism underlying the leptin-induced depolarization. On the other hand, the I–V curve of leptin-induced outward currents is characterized by positive slope conductance and has an average reversal potential of −88 ± 3 mV, suggesting that an increase in potassium conductance may underlie leptin-induced hyperpolarization. Most of the leptin-responsive DMNV neurons were identified as being parasympathetic preganglionic neurons. These results suggest that the DMNV is one of the central target sites of leptin, and leptin can regulate parasympathetic outflow from the DMNV by directly acting on the parasympathetic preganglionic neurons of the DMNV.

scholarly journals Spatial organization of neurons in the dorsal motor nucleus of the vagus synapsing with intragastric cholinergic and nitric oxide/VIP neurons in the rat

2008 ◽  
Vol 294 (5) ◽  
pp. G1201-G1209 ◽  
Author(s):  
Shi-Yi Zhou ◽  
Yuan-Xu Lu ◽  
HongRen Yao ◽  
Chung Owyang
Keyword(s):  
Nitric Oxide ◽  
Spatial Organization ◽  
Cholinergic Neurons ◽  
Motor Nucleus ◽  
Neural Pathways ◽  
Myenteric Neurons ◽  
Preganglionic Neurons ◽  
Gastric Contraction ◽  
Dorsal Motor Nucleus ◽  
Contraction And Relaxation

The dorsal motor nucleus of the vagus (DMV) contains preganglionic neurons that control gastric motility and secretion. Stimulation of different parts of the DMV results in a decrease or an increase in gastric motor activities, suggesting a spatial organization of vagal preganglionic neurons in the DMV. Little is known about how these preganglionic neurons in the DMV synapse with different groups of intragastric motor neurons to mediate contraction or relaxation of the stomach. We used pharmacological and immunohistochemical methods to characterize intragastric neural pathways involved in mediating gastric contraction and relaxation in rats. Microinjections of l-glutamate (l-Glu) into the rostral or caudal DMV produced gastric contraction and relaxation, respectively, in a dose-related manner. Intravenous infusion of hexamethonium blocked these actions, suggesting mediation via preganglionic cholinergic pathways. Atropine inhibited gastric contraction by 85.5 ± 4.5%. Gastric relaxation was reduced by intravenous administration of NG-nitro-l-arginine methyl ester (l-NAME; 52.5 ± 11.9%) or VIP antagonist (56.3 ± 14.9%). Combined administration of l-NAME and VIP antagonist inhibited gastric relaxation evoked by l-Glu (87.8 ± 4.3%). Immunohistochemical studies demonstrated choline acetyltransferase immunoreactivity in response to l-Glu microinjection into the rostral DMV in 88% of c-Fos-positive intragastric myenteric neurons. Microinjection of l-Glu into the caudal DMV evoked expression of nitric oxide (NO) synthase and VIP immunoreactivity in 81 and 39%, respectively, of all c-Fos-positive intragastric myenteric neurons. These data indicate spatial organization of the DMV. Depending on the location, microinjection of l-Glu into the DMV may stimulate intragastric myenteric cholinergic neurons or NO/VIP neurons to mediate gastric contraction and relaxation.

IV. Current concepts of vagal efferent projections to the gut

2003 ◽  
Vol 284 (3) ◽  
pp. G357-G366 ◽  
Author(s):  
Howard Y. Chang ◽  
Hiroshi Mashimo ◽  
Raj K. Goyal
Keyword(s):  
Motor Neurons ◽  
Nucleus Ambiguus ◽  
Inhibitory Neurons ◽  
Cholinergic Innervation ◽  
Motor Nucleus ◽  
Striated Muscles ◽  
Preganglionic Neurons ◽  
Excitatory Neurotransmitters ◽  
Efferent Projections ◽  
Motor Effects

Vagal efferents, consisting of distinct lower motor and preganglionic parasympathetic fibers, constitute the motor limb of vagally mediated reflexes. Arising from the nucleus ambiguus, vagal lower motor neurons (LMN) mediate reflexes involving striated muscles of the orad gut. LMNs provide cholinergic innervation to motor end plates that are inhibited by myenteric nitrergic neurons. Preganglionic neurons from the dorsal motor nucleus implement parasympathetic motor and secretory functions. Cholinergic preganglionic neurons form parallel inhibitory and excitatory vagal pathways to smooth muscle viscera and stimulate postganglionic neurons via nicotinic and muscarinic receptors. In turn, the postganglionic inhibitory neurons release ATP, VIP, and NO, whereas the excitatory neurons release ACh and substance P. Vagal motor effects are dependent on the viscera's intrinsic motor activity and the interaction between the inhibitory and excitatory vagal influences. These interactions help to explain the physiology of esophageal peristalsis, gastric motility, lower esophageal sphincter, and pyloric sphincter. Vagal secretory pathways are predominantly excitatory and involve ACh and VIP as the postganglionic excitatory neurotransmitters. Vagal effects on secretory functions are exerted either directly or via release of local mediators or circulating hormones.

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