Neuronal activity recorded extracellularly in chronically decentralized in situ canine middle cervical ganglia

1986 ◽  
Vol 64 (7) ◽  
pp. 1038-1046 ◽  
Author(s):  
J. A. Armour
Keyword(s):  
Nervous System ◽  
Thoracic Wall ◽  
Identified Neurons ◽  
Pulmonary Tissue ◽  
Local Circuit ◽  
Local Circuit Neurons ◽  
Cervical Ganglion ◽  
Cervical Ganglia ◽  
Ganglion Neurons

In chronically decentralized in situ middle cervical ganglia of 10 dogs, 279 spontaneously active neurons were identified. One hundred and ten (39%) of these were spontaneously active during specific phases of the cardiac cycle, primarily during systole, and the activity of nearly half of these cardiovascular-related neurons was modified by gentle mechanical distortion of the vena cavae, heart, or thoracic aorta. Another 60 (22%) of the identified neurons had respiratory – related activity, but the activity of only 2 of them was modified by gentle mechanical distortion of pulmonary tissue. Twenty-nine of the other 109 identified neurons were activated by gentle mechanical distortion of localized regions of the neck, ventral thoracic wall, or ventral abdominal wall. Because of the presence of activity in the chronically decentralized middle cervical ganglion, these data infer that some afferent neurons are located in the thoracic autonomic nervous system. Some middle cervical ganglion neurons were activated by single 1–4 ms stimuli delivered to a nerve connected to the ganglion. During repetitive stimuli delivered at 0.5 Hz none were activated after a fixed latency following the stimuli. Many more neurons were activated by 10- to 200-ms trains of 1–4 ms stimuli delivered with interstimulus intervals of 1–10 ms. The majority of these neurons could still be activated electrically after the administration of cholinergic and adrenergic pharmacological blocking agents. As the spontaneously active neurons, as well as those which were not spontaneously active, which were recorded were not consistently activated by single 1–4 ms stimuli delivered individually to every nerve connected to the middle cervical ganglion, they presumably did not project axons into these nerves and thus are presumed not to be afferent or efferent postganglionic neurons but rather to be local circuit neurons. It is concluded that local circuit neurons in the middle cervical ganglion are involved in regulating cardiovascular, respiratory, and other tissues and can function independent of neurons in the central nervous system.

Neuronal activity recorded extracellularly from in situ canine mediastinal ganglia

1988 ◽  
Vol 66 (1) ◽  
pp. 119-127 ◽  
Author(s):  
J. A. Armour ◽  
R. D. Janes
Keyword(s):  
Vena Cava ◽  
Systolic Pressure ◽  
Thoracic Wall ◽  
Identified Neurons ◽  
Positive Pressure ◽  
Related Activity ◽  
Local Circuit ◽  
Local Circuit Neurons ◽  
Ganglion Neurons

Spontaneous activity of 226 neurons was recorded from in situ mediastinal ganglia in 10 dogs. Forty-two percent of these were active during specific phases of the cardiac cycle, primarily during systole. Cardiovascular-related activity occurred when systolic pressure was between ~70 and 185 mmHg (1 mmHg = 133.3 Pa) whether the pressure was altered by positive inotropic pharmacological agents or cross clamping of the aorta. Twenty percent of the identified neurons displayed respiratory-related activity which occurred during positive pressure inflation or deflation. Thirty-eight percent of the identified neurons displayed bursts of activity or sporadic activity. The activity of 17% of the identified neurons was altered by gentle mechanical distortion of localized regions of the neck, left elbow, ventral thoracic wall, ventral abdominal wall, superior vena cava, right ventricle, or aorta. In the majority of instances cardiovascular- or respiratory-related activity persisted following acute decentralization, indicating that neurons in mediastinal ganglia can function in the absence of influences of central nervous system neurons. Five percent of the identified neurons were activated by single 1–4 ms, 10–20 V stimuli delivered at 0.5 Hz to the nerves connected with either the cranial or the caudal poles of the mediastinal ganglion or the ansae. These neurons were activated after a fixed latency when 0.5 Hz was used and in most instances when 10 Hz was used. These data indicate that 5% or less of the neurons identified projected axons out of the mediastinal ganglia investigated. As the remainder of the neurons identified were not consistently activated after single stimuli delivered individually to the nerves connected directly or indirectly with the mediastinal ganglion, they presumably did not project axons out of the ganglion and thus were considered to be local circuit neurons. Since a number of these local circuit neurons were activated by trains of stimuli delivered to the ipsilateral cardiopulmonary nerves, ansae, rami, sympathetic chain, or cervical vagosympathetic complex, it appears that neural information from a number of sources can modify the behaviour of mediastinal ganglion neurons, substantiating the evidence obtained when various tissues were distorted. Some of the neurons in mediastinal ganglia continued to be activated by trains of stimuli following the administration of hexamethonium, atropine, propranolol, and phentolamine, albeit usually with different latencies of activation. These data support the contention that synaptic mechanisms other than cholinergic and adrenergic ones may exist in mediastinal ganglia, as has been proposed to occur with respect to neurons in the major intrathoracic ganglia. The results of the present experiments indicate that neurons in mediastinal ganglia are involved in cardiovascular and respiratory regulation and that they can be influenced by neural structures in a variety of tissues, some of which are relatively remote from the ganglion. It appears that some of these may be local circuit neurons. Thus neurons in ganglia adjacent to the heart and lungs can behave similarly to neurons located in the middle cervical and stellate ganglia.

Activity of in situ middle cervical ganglion neurons in dogs, using extracellular recording techniques

1985 ◽  
Vol 63 (6) ◽  
pp. 704-716 ◽  
Author(s):  
J. A. Armour
Keyword(s):  
Neuronal Activity ◽  
Action Potentials ◽  
Vena Cava ◽  
Extracellular Recording ◽  
Cervical Ganglion ◽  
Cervical Ganglia ◽  
Ganglion Neurons ◽  
Stimulation Of ◽  
Recording Techniques

Neuronal activity in the in situ middle cervical ganglion of dogs was investigated using extracellular recording techniques. The recorded action potentials were frequently active during specific phases of the cardiac cycle, particularly during systole, and this activity persisted following acute decentralization of the ganglion. The activity of these action potentials was modified when systemic arterial pressure was altered by isoproterenol, noradrenaline, adrenaline, or partial occlusion of the aorta, whether in the intact or acutely decentralized preparation. These neurons were active between systolic pressures of 70 and 180 mmHg (1 mmHg = 133.322 Pa). Action potentials were frequently modified by mechanical distortion of the superior vena cava, ventricular epicardium, or adventitia of the aorta, whether the preparation was acutely decentralized or not. Seventy percent of these action potentials were unaffected by stimulation (1 ms, 4 V, 0.5 Hz) of a cardiopulmonary nerve and 27% were suppressed by such stimulation. Five of the neurons were activated by such stimulation. It is presumed that the latter neurons had axons in a cardiopulmonary nerve and most likely were efferent sympathetic postganglionic neurons. Sixty-three percent of these spontaneously active phase-locked units were modified by stimulation of a ramus or an ansa. It is postulated that some of the neurons in the middle cervical ganglia can be modified by afferent axons arising from receptors in thoracic organs, in particular from the great vessels and heart, whether in an intact or acutely decentralized preparation. The majority of these neurons are presumed not to be afferent neurons or efferent postganglionic neurons, as they are not activated directly by electrical stimulation of axons in cardiopulmonary nerves. Rather they are presumed to be interneurons. These results lend support to the thesis that considerable integration of neuronal activity related to thoracic cardiovascular dynamics occurs within the middle cervical ganglia of dogs.

Intracellular transduction mechanisms for the slow synaptic events

1992 ◽  
Vol 70 (S1) ◽  
pp. S44-S50 ◽  
Author(s):  
Haruo Kobayashi ◽  
Sumiko Mochida ◽  
Susumu Y. Takahashi
Keyword(s):  
Superior Cervical Ganglion ◽  
Action Potentials ◽  
Acetylcholine Receptors ◽  
Second Messengers ◽  
Muscarinic Acetylcholine Receptors ◽  
Characteristic Change ◽  
Receptor Subtypes ◽  
Cervical Ganglion ◽  
Cervical Ganglia ◽  
Ganglion Neurons

Electrical activities of the postganglionic neurons in the superior cervical ganglia of rabbits are modulated in various ways following activation of the subtypes of muscarinic acetylcholine receptors, (i) M1 receptors mediate a slow depolarization consisting of at least three types of ionic conductance changes, and one of these is possibly mediated by cyclic GMP. (ii) M2 receptors mediate a slow hyperpolarization that seems to be generated by inositol triphosphate derived from phosphatidylinositol breakdown. (iii) M2 receptors also cause, through an activation of C kinase, a suppression of Ca entry during action potentials that results in a characteristic change in the action potentials and thereby modulates excitability of superior cervical ganglion neurons. Each subtype of muscarinic receptors thus regulates different pathways of intracellular transduction and modulates the electrical signaling of sympathetic neurons.Key words: superior cervical ganglion, electrical signals, muscarinic responses, muscarinic receptor subtypes, second messengers.

scholarly journals Dorsal spinal cord stimulation obtunds the capacity of intrathoracic extracardiac neurons to transduce myocardial ischemia

2009 ◽  
Vol 297 (2) ◽  
pp. R470-R477 ◽  
Author(s):  
Jeffrey L. Ardell ◽  
René Cardinal ◽  
Michel Vermeulen ◽  
J. Andrew Armour
Keyword(s):  
Spinal Cord ◽  
Nervous System ◽  
Myocardial Ischemia ◽  
Spinal Cord Stimulation ◽  
Ventricular Pacing ◽  
Cervical Ganglion ◽  
Rapid Ventricular Pacing ◽  
Local Reflex ◽  
Electrical Neuromodulation ◽  
Ganglion Neurons

Populations of intrathoracic extracardiac neurons transduce myocardial ischemia, thereby contributing to sympathetic control of regional cardiac indices during such pathology. Our objective was to determine whether electrical neuromodulation using spinal cord stimulation (SCS) modulates such local reflex control. In 10 anesthetized canines, middle cervical ganglion neurons were identified that transduce the ventricular milieu. Their capacity to transduce a global (rapid ventricular pacing) vs. regional (transient regional ischemia) ventricular stress was tested before and during SCS (50 Hz, 0.2 ms duration at 90% MT) applied to the dorsal aspect of the T1 to T4 spinal cord. Rapid ventricular pacing and transient myocardial ischemia both activated cardiac-related middle cervical ganglion neurons. SCS obtunded their capacity to reflexly respond to the regional ventricular ischemia, but not rapid ventricular pacing. In conclusion, spinal cord inputs to the intrathoracic extracardiac nervous system obtund the latter's capacity to transduce regional ventricular ischemia, but not global cardiac stress. Given the substantial body of literature indicating the adverse consequences of excessive adrenergic neuronal excitation on cardiac function, these data delineate the intrathoracic extracardiac nervous system as a potential target for neuromodulation therapy in minimizing such effects.

Activity of canine in situ left atrial ganglion neurons

1990 ◽  
Vol 259 (4) ◽  
pp. H1207-H1215 ◽  
Author(s):  
J. A. Armour ◽  
D. A. Hopkins
Keyword(s):  
Left Atrial ◽  
Systolic Pressure ◽  
Ventral Surface ◽  
Identified Neurons ◽  
Related Activity ◽  
Ganglionated Plexi ◽  
Respiratory Dynamics ◽  
Ganglion Neurons ◽  
Fat Pads

The responses of 135 spontaneously active neurons were recorded from ganglionated plexi located in the three epicardial fat pads on the ventral surface of the left atrium of ten dogs. Ganglia, some of which were adjacent to the recording sites, containing varying numbers of neurons were identified throughout these fat pads. Spontaneous activity in 50% of the identified neurons was correlated with specific phases of the cardiac cycle when arterial systolic pressure was between approximately 70 and 180 mmHg and in 28% it was correlated with the respiratory cycle. More neurons displaying cardiovascular-related activity were recorded when systolic pressure was increased after administration of positive inotropic agents or aortic occlusion. However, when systolic pressure increased above approximately 150 mmHg the number of active neurons decreased, and when pressure reached approximately 180 mmHg no activity was recorded. The activity of 36% of identified neurons was altered when discrete regions of the heart, great thoracic vessels, lungs, neck, upper limb, chest wall, or abdominal wall were mechanically distorted by gentle touch. After acute decentralization of the intrathoracic nervous system some neurons still displayed spontaneous cardiovascular- or respiratory-related activity. Single stimuli or trains of stimuli delivered to the vagosympathetic complexes, stellate ganglia, or cardiopulmonary nerves activated neurons in intact or acutely decentralized preparations. It is concluded that ventral left atrial ganglionated plexi neurons display activity related to cardiovascular or respiratory dynamics, and that these neurons are influenced by sympathetic and parasympathetic efferent axons, as well as by cardiac and other mechanoreceptors.

Activity of in situ stellate ganglion neurons of dogs recorded extracellularly

1986 ◽  
Vol 64 (2) ◽  
pp. 101-111 ◽  
Author(s):  
J. A. Armour
Keyword(s):  
Short Duration ◽  
High Frequency ◽  
Cardiac Cycle ◽  
Superior Vena ◽  
Stellate Ganglion ◽  
Vena Cava ◽  
Thoracic Wall ◽  
Stellate Ganglia ◽  
Ganglion Neurons

Activity was recorded from 145 neurons in the in situ stellate ganglia of 36 dogs. The activity of 28 of these neurons, most of them located in the ganglia's cranial medial region, was related to the cardiac cycle primarily during systole. The activity of 16 of these cardiovascular-related neurons was modified by gentle mechanical distortion of the superior vena cava (1), heart (4), or thoracic aorta (11). Forty-one of the neurons were modified by respiration, with 17 being phase-locked to the respiratory cycle. Other neurons were activated by gentle mechanical distortion of localized regions of the thoracic wall (21% of all neurons), neck (18%), skin of the left foreleg (10%), or the mediastinum adjacent to the stellate ganglion (3%). Acutely decentralizing the stellate ganglion abolished the spontaneous activity of some, but not all, of these neurons including the respiratory or cardiovascular-related neurons. In the intact or acutely decentralized stellate ganglion, few neurons were activated by single short duration (1 – 4 ms) stimuli delivered to nerves attached directly or indirectly to the ganglion; however, most were activated by brief high frequency stimuli delivered in trains of 20–200 ms, or by single stimuli lasting 20–200 ms. As most cardiovascular, respiratory, or neck-related neurons in the stellate ganglion were not activated by single brief stimuli delivered to the cardiopulmonary nerves or vagosympathetic trunks, presumably they did not project their axons into the neck or thoracic organs. Thus, they were considered to be interneurons. It is postulated that interneurons in stellate ganglia can be modified by afferent receptors located in tissues of the neck, lungs, heart, or great thoracic vessels, whether the ganglion is intact or acutely decentralized. In addition, neurons in the stellate ganglion can be modified by mechanoreceptors located in the thoracic wall, abdominal wall, foreleg, or adjacent mediastinum. The majority of these neurons are activated by trains of impulses rather than single short duration impulses.

Evidence for a Blood Ganglion Barrier in the Superior Cervical Ganglion of the Rat

1982 ◽  
Vol 40 ◽  
pp. 204-204
Author(s):  
D. M. DePace
Keyword(s):  
Blood Vessels ◽  
Superior Cervical Ganglion ◽  
Peripheral Nerves ◽  
Time Schedule ◽  
Transmission Electron ◽  
Cervical Ganglion ◽  
The Central Nervous System ◽  
Cervical Ganglia ◽  
Capillary Circulation ◽  
And Control

The majority of blood vessels in the superior cervical ganglion possess a continuous endothelium with tight junctions. These same features have been associated with the blood brain barrier of the central nervous system and peripheral nerves. These vessels may perform a barrier function between the capillary circulation and the superior cervical ganglion. The permeability of the blood vessels in the superior cervical ganglion of the rat was tested by intravenous injection of horseradish peroxidase (HRP). Three experimental groups of four animals each were given intravenous HRP (Sigma Type II) in a dosage of.08 to.15 mg/gm body weight in.5 ml of.85% saline. The animals were sacrificed at five, ten or 15 minutes following administration of the tracer. Superior cervical ganglia were quickly removed and fixed by immersion in 2.5% glutaraldehyde in Sorenson's.1M phosphate buffer, pH 7.4. Three control animals received,5ml of saline without HRP. These were sacrificed on the same time schedule. Tissues from experimental and control animals were reacted for peroxidase activity and then processed for routine transmission electron microscopy.

scholarly journals Apoptotic Cells, Including Macrophages, Are Prominent in Theiler's Virus-Induced Inflammatory, Demyelinating Lesions

2003 ◽  
Vol 77 (7) ◽  
pp. 4383-4388 ◽  
Author(s):  
Brian P. Schlitt ◽  
Matthew Felrice ◽  
Mary Lou Jelachich ◽  
Howard L. Lipton
Keyword(s):  
Central Nervous System ◽  
T Cells ◽  
Nervous System ◽  
In Situ Hybridization ◽  
Apoptotic Cells ◽  
Theiler's Virus ◽  
Demyelinating Lesions ◽  
Encephalomyelitis Virus ◽  
Mouse Central Nervous System

ABSTRACT Theiler's murine encephalomyelitis virus (TMEV) persists in the mouse central nervous system principally in macrophages, and infected macrophages in culture undergo apoptosis. We have detected abundant apoptotic cells in perivascular cuffs and inflammatory, demyelinating lesions of SJL mice chronically infected with TMEV. T cells comprised 74% of apoptotic cells, while 8% were macrophages, 0.6% were astrocytes, and ∼17% remained unidentified. In situ hybridization revealed viral RNA in ∼1% of apoptotic cells.

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