Aortic nerve-activated cardioinhibitory neurons and interneurons

Unit activity evoked by electrical stimulation of the aortic and vagus nerves was recorded in the dorsal motor nucleus and nucleus solitarius of unanesthetized rabbits. Cardioinhibitory cells which showed antidromic activation to stimulation of the vagus nerve and synaptic activation to stimulation of the aortic nerve were localized in lateral dorsal motor nucleus 0.5-0.8 mm anterior of the obex. Additionally, units were found that appeared to be interneurons in the medullary pathway subserving baroreceptor reflex effects on cardioinhibitory neurons. These cells were activated by aortic, and usually vagus, nerve stimulation, appeared to be polysynaptically activated, and were located in medial nucleus solitarius rostral to the obex. Neurons reflecting a cardiac rhythm but not activated by aortic nerve stimulation were also observed.

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Acute resetting of baroreceptor reflex in rabbits: a central component

AJP Heart and Circulatory Physiology ◽

10.1152/ajpheart.1986.250.5.h866 ◽

1986 ◽

Vol 250 (5) ◽

pp. H866-H870 ◽

Cited By ~ 5

Author(s):

D. L. Kunze

Keyword(s):

Arterial Pressure ◽

Test Stimulus ◽

Nerve Stimulation ◽

Sympathetic Activity ◽

Constant Stimulus ◽

Baroreceptor Reflex ◽

Pressure Response ◽

Stimulus Period ◽

Aortic Nerve ◽

Stimulation Of

Electrical stimulation of the aortic nerve of the anesthetized rabbit was used to determine whether there is a central nervous system component to acute resetting of the baroreceptor reflex. After stimulation of the aortic nerve for 5 min at 10 Hz, a ramp test stimulus to the nerve produced a reflex arterial pressure response that was attenuated as compared with that produced by the same ramp prior to the five-min stimulation period. Renal sympathetic nerve activity was recorded simultaneously to determine whether a reduction in the magnitude of the reflex inhibition of sympathetic activity produced by the depressor nerve stimulation could account for the attenuated arterial pressure response. Renal activity during the test ramp was reduced to the same value both before and after the constant stimulus period and thus did not correlate with the attenuated pressure response. There was, however, prolonged inhibition of tonic sympathetic activity after the 5-min stimulus period such that during the test stimulus there was less sympathetic activity to inhibit. The results were similar when sympathetic activity was recorded from branches of the sciatic nerve and from thoracic postganglionic nerves. In these nerves the period of prolonged inhibition after aortic nerve stimulation was up to 5 min. The attenuated pressure response to baroreceptor nerve stimulation after a constant stimulus appears to reflect the reduced change in sympathetic activity rather than the value to which the sympathetic activity falls.

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Optical Approaches to Functional Organization of Glossopharyngeal and Vagal Motor Nuclei in the Embryonic Chick Hindbrain

Journal of Neurophysiology ◽

10.1152/jn.2002.88.1.383 ◽

2002 ◽

Vol 88 (1) ◽

pp. 383-393 ◽

Cited By ~ 20

Author(s):

Katsushige Sato ◽

Hiraku Mochida ◽

Itaru Yazawa ◽

Shinichi Sasaki ◽

Yoko Momose-Sato

Keyword(s):

Vagus Nerve ◽

Developmental Stages ◽

Functional Organization ◽

Signal Amplitude ◽

Optical Recording ◽

Single Peak ◽

Motor Nucleus ◽

Vagus Nerves ◽

Dorsal Motor Nucleus ◽

Motor Nuclei

We investigated the functional organization of the glossopharyngeal and vagal motor nuclei during embryogenesis using multiple-site optical recording with a fast voltage-sensitive dye. Intact brain stem preparations with glossopharyngeal and vagus nerves were dissected from 4- to 8-day-old chick embryos. Electrical responses evoked by glossopharyngeal/vagus nerve stimulation were optically recorded from many loci of the stained preparations. In 4- to 6-day-old preparations, action potential-related fast spikelike signals were detected from the nucleus of the glossopharyngeal nerve and the dorsal motor nucleus of the vagus nerve. Contour line maps of the signal amplitude showed multiple-peak patterns, suggesting that the neurons and/or their activity were not uniformly distributed within the nuclei at early developmental stages. As development proceeded from 4 to 6 days, the peaks fused with each other and the number of peaks decreased gradually. In most 7- and 8-day-old preparations, only a single peak was identified in the nuclei, and the distribution of the signal amplitude formed a layered pattern surrounding the peak-signal area. These results suggest that functional organization of the motor nuclei in the embryonic hindbrain changes dynamically with development, resulting in a rearrangement of functional nuclear cores from multiple-peaks to a single peak.

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Increases in Plasma Insulin Levels in Response to Electrical Stimulation of the Dorsal Motor Nucleus of the Vagus Nerve*

Endocrinology ◽

10.1210/endo-112-3-904 ◽

1983 ◽

Vol 112 (3) ◽

pp. 904-910 ◽

Cited By ~ 59

Author(s):

E. IONESCU ◽

F. ROHNER-JEANRENAUD ◽

H.-R. BERTHOUD ◽

B. JEANRENAUD

Keyword(s):

Electrical Stimulation ◽

Vagus Nerve ◽

Plasma Insulin ◽

Motor Nucleus ◽

Insulin Levels ◽

Dorsal Motor Nucleus ◽

Plasma Insulin Levels ◽

Stimulation Of

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Localization of sites within dorsal motor nucleus of vagus that affect gastric motility

AJP Gastrointestinal and Liver Physiology ◽

10.1152/ajpgi.1985.249.1.g73 ◽

1985 ◽

Vol 249 (1) ◽

pp. G73-G84 ◽

Cited By ~ 6

Author(s):

F. D. Pagani ◽

W. P. Norman ◽

D. K. Kasbekar ◽

R. A. Gillis

Keyword(s):

Heart Rate ◽

Electrical Stimulation ◽

Arterial Pressure ◽

Gastric Motility ◽

Motor Nucleus ◽

Fast Blue ◽

Medial Nucleus ◽

Dorsal Motor Nucleus ◽

Propantheline Bromide ◽

Stimulation Of

The purpose of our study was to determine the localization of sites within the dorsal motor nucleus of the vagus (DMV) of the cat that when stimulated would increase gastric motility. To do this, two types of experiments were performed. First, the retrograde tracer fast blue was injected into the antrum and pylorus, and labeled neurons in the DMV were identified. Second, electrical stimulation was performed in areas of the DMV labeled with fast blue as well as in nearby areas with no labeling while monitoring gastric motility, arterial pressure, and heart rate. Results from the first type of studies revealed that peak labeling in the DMV occurred between 0.56 and 1.56 mm rostral to obex. Electrical stimulation in this area using 100 microA, 0.2 ms duration pulses, and 50 Hz resulted in increases in antral and pyloric contractions in 20 animals. The magnitude of pyloric and antral responses elicited by stimulation of the DMV generally correlated to the number of cell bodies labeled with fast blue within the DMV. No changes in arterial pressure occurred, and only a slight (-4%) decrease in heart rate was observed. Maximal increases in motility occurred with 20 Hz (antrum) or 100 Hz (pylorus). These increases in motility were maintained even at 200- and 400-Hz stimulation. Ipsilateral vagotomy or pretreatment with propantheline bromide prevented the increases in gastric motility produced by electrical stimulation of the DMV. Electrical stimulation of more rostral sites in the DMV, the medial nucleus of the solitary tract (NTS), and an area within 1.0 mm medial to the DMV resulted in attenuated or no motility responses. Stimulation of the medial nucleus of the NTS did result in pronounced slowing in heart rate (-61 +/- 21 beats/min). These results suggest that there is a localization of a “stomach area” within the DMV and that electrical stimulation of this area results in gastric motility responses that are mediated by vagal fibers projecting directly to the stomach. In addition, electrical stimulation of the DMV results in selective effects on the gastrointestinal tract in that no pronounced changes in heart rate and arterial pressure occur.

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Effects of Electrical Stimulation at Different Locations in the Central Nucleus of Amygdala on Gastric Motility and Spike Activity

Physiological Research ◽

10.33549/physiolres.933125 ◽

2016 ◽

pp. 693-700 ◽

Cited By ~ 4

Author(s):

F. HE ◽

H.-B. AI

Keyword(s):

Electrical Stimulation ◽

Gastric Motility ◽

Spike Activity ◽

Central Nucleus ◽

Motor Nucleus ◽

Dorsal Vagal Complex ◽

Motility Index ◽

Medial Nucleus ◽

Dorsal Motor Nucleus ◽

Stimulation Of

The aim of the study was to determine the effects of electrical stimulation of different locations in the central nucleus of amygdala (CNA) on gastric motility and spike activity in dorsal vagal complex. Gastric motility index (GMI) and firing rate (FR) of dorsal vagal complex neurons were measured in adult Wistar rats respectively. Neuronal spikes in dorsal vagal complex (DVC) were recorded extracellularly with single-barrel glass microelectrodes. Each type of responses elicited by electrical stimulation in medial (CEM) and lateral (CEL) subdivisions of CNA were recorded, respectively. GMI was significantly increased after stimulation of CEM (p<0.01), and significantly decreased in response to CEL stimulation (p<0.01). After stimulation of CEM, FR in medial nucleus of the solitary tract (mNST) decreased by 31.6 % (p<0.01) and that in dorsal motor nucleus of the vagus (DMNV) increased by 27.1 % (p<0.01). On the contrary, FR in mNST increased (p<0.01) and that in DMNV decreased in response to CEL stimulation (p<0.05). In conclusions, our findings indicated that different loci of CNA may mediate differential effects on gastric activity via changes in the firing of brainstem neurons controlling gut activity.

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Dorsal motor nucleus of the vagus: a site for evoking simultaneous changes in crural diaphragm activity, lower esophageal sphincter pressure, and fundus tone

AJP Regulatory Integrative and Comparative Physiology ◽

10.1152/ajpregu.00391.2007 ◽

2008 ◽

Vol 294 (1) ◽

pp. R121-R131 ◽

Cited By ~ 18

Author(s):

Mark Niedringhaus ◽

Patrick G. Jackson ◽

Stephen R. T. Evans ◽

Joseph G. Verbalis ◽

Richard A. Gillis ◽

...

Keyword(s):

Smooth Muscle ◽

Lower Esophageal Sphincter ◽

Lower Esophageal Sphincter Pressure ◽

Motor Nucleus ◽

Sphincter Pressure ◽

Vagus Nerves ◽

Dorsal Motor Nucleus ◽

Esophageal Sphincter ◽

Crural Diaphragm ◽

Stimulation Of

The sphincter mechanism at the esophagogastric junction includes smooth muscle of the lower esophagus and skeletal muscle of the crural diaphragm (CD). Smooth muscle is known to be under the control of the dorsal motor nucleus of the vagus (DMV), while central nervous system (CNS) control of the CD is unknown. The main purposes of our study were to determine the CNS site that controls the CD and whether simultaneous changes in lower esophageal sphincter (LES) pressure and CD activity occur when this site is activated. Experiments were performed on anesthetized male ferrets whose LES pressure, CD activity, and fundus tone were monitored. To activate DMV neurons, l-glutamate was microinjected unilaterally into the DMV at three areas: intermediate, rostral, and caudal. Stimulation of the intermediate DMV decreased CD activity (−4.8 ± 0.1 bursts/min and −0.3 ± 0.01 mV) and LES pressure (−13.2 ± 2.0 mmHg; n = 9). Stimulation of this brain site also produced an increase in fundus tone. Stimulation of the rostral DMV elicited increases in the activity of all three target organs ( n = 5). Stimulation of the caudal DMV had no effect on the CD but did decrease both LES pressure and fundus tone ( n = 5). All changes in LES pressure, fundus tone, and some DMV-induced changes in CD activity (i.e., bursts/min) were prevented by ipsilateral vagotomy. Our data indicate that simultaneous changes in activity of esophagogastric sphincters and fundus tone occur from rostral and intermediate areas of the DMV and that these changes are largely mediated by efferent vagus nerves.

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Direct amygdaloid projections to the dorsal motor nucleus of the vagus nerve: a light and electron microscopic study in the rat

Brain Research ◽

10.1016/0006-8993(83)91182-4 ◽

1983 ◽

Vol 280 (1) ◽

pp. 143-147 ◽

Cited By ~ 42

Author(s):

Yoshiki Takeuchi ◽

Sachi Matsushima ◽

Ryotaro Matsushima ◽

David A. Hopkins

Keyword(s):

Vagus Nerve ◽

Microscopic Study ◽

Electron Microscopic Study ◽

Motor Nucleus ◽

Electron Microscopic ◽

Dorsal Motor Nucleus

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THE INFLUENCE OF THE VAGUS NERVES UPON CONDUCTION BETWEEN AURICLES AND VENTRICLES IN THE DOG DURING AURICULAR FIBRILLATION

Journal of Experimental Medicine ◽

10.1084/jem.24.5.605 ◽

1916 ◽

Vol 24 (5) ◽

pp. 605-619 ◽

Cited By ~ 1

Author(s):

G. Canby Robinson

Keyword(s):

Vagus Nerve ◽

Vagus Nerves ◽

The Right ◽

Left Vagus ◽

Stimulation Of

The experiments that have been reported indicate that stimulation of either the right vagus or the left vagus nerve is equally effectual in blocking impulses from the auricles to the ventricles when auricular fibrillation is present. Stimulation of the left vagus nerve is as effectual in blocking impulses from the normally beating auricles as from the auricles when in a state of fibrillation, and the type of auricular activity has apparently no influence on the effect which stimulation of the left vagus has on auriculoventricular conduction.

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Distribution of vagal cardioinhibitory neurons in the medulla of the cat

AJP Regulatory Integrative and Comparative Physiology ◽

10.1152/ajpregu.1980.238.1.r57 ◽

1980 ◽

Vol 238 (1) ◽

pp. R57-R64 ◽

Cited By ~ 4

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.

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