Responses and Afferent Pathways of Superficial and Deeper C1–C2 Spinal Cells to Intrapericardial Algogenic Chemicals in Rats

2001 ◽  
Vol 85 (4) ◽  
pp. 1522-1532 ◽  
Author(s):  
Chao Qin ◽  
Margaret J. Chandler ◽  
Kenneth E. Miller ◽  
Robert D. Foreman
Keyword(s):  
Afferent Input ◽  
Vagal Afferents ◽  
Male Rats ◽  
Prostaglandin E ◽  
Joint Movement ◽  
Spinal Neurons ◽  
Afferent Pathways ◽  
Bilateral Vagotomy ◽  
Cardiac Afferents ◽  
Stimulation Of

Electrical stimulation of vagal afferents or cardiopulmonary sympathetic afferent fibers excites C1–C2spinal neurons. The purposes of this study were to compare the responses of superficial (depth <0.35 mm) and deeper C1–C2 spinal neurons to noxious chemical stimulation of cardiac afferents and determine the relative contribution of vagal and sympathetic afferent pathways for transmission of noxious cardiac afferent input to C1–C2 neurons. Extracellular potentials of single C1–C2 neurons were recorded in pentobarbital anesthetized and paralyzed male rats. A catheter was placed in the pericardial sac to administer a mixture of algogenic chemicals (0.2 ml) that contained adenosine (10− 3 M), bradykinin, histamine, serotonin, and prostaglandin E2(10− 5 M each). Intrapericardial chemicals changed the activity of 20/106 (19%) C1–C2 spinal neurons in the superficial laminae, whereas 76/147 (52%) deeper neurons responded to cardiac noxious input ( P < 0.01). Of 96 neurons responsive to cardiac inputs, 48 (50%) were excited (E), 41 (43%) were inhibited (I), and 7 were excited/inhibited (E-I) by intrapericardial chemicals. E or I neurons responsive to intrapericardial chemicals were subdivided into two groups: short-lasting (SL) and long-lasting (LL) response patterns. In superficial gray matter, excitatory responses to cardiac inputs were more likely to be LL-E than SL-E neurons. Mechanical stimulation of the somatic field from the head, neck, and shoulder areas excited 85 of 95 (89%) C1–C2 spinal neurons that responded to intrapericardial chemicals; 31 neurons were classified as wide dynamic range, 49 were high threshold, 5 responded only to joint movement, and no neuron was classified as low threshold. For superficial neurons, 53% had small somatic fields and 21% had bilateral fields. In contrast, 31% of the deeper neurons had small somatic fields and 46% had bilateral fields. Ipsilateral cervical vagotomy interrupted cardiac noxious input to 8/30 (6 E, 2 I) neurons; sequential transection of the contralateral cervical vagus nerve (bilateral vagotomy) eliminated the responses to intrapericardial chemicals in 4/22 (3 E, 1 I) neurons. Spinal transection at C6–C7 segments to interrupt effects of sympathetic afferent input abolished responses to cardiac input in 10/10 (7 E, 3 I) neurons that still responded after bilateral vagotomy. Results of this study support the concept that C1–C2 superficial and deeper spinal neurons play a role in integrating cardiac noxious inputs that travel in both the cervical vagal and/or thoracic sympathetic afferent nerves.

Responses and Afferent Pathways of C1–C2 Spinal Neurons to Cervical and Thoracic Esophageal Stimulation in Rats

2004 ◽  
Vol 91 (5) ◽  
pp. 2227-2235 ◽  
Author(s):  
Chao Qin ◽  
Margaret J. Chandler ◽  
Chuanchau J. Jou ◽  
Robert D. Foreman
Keyword(s):  
Male Rats ◽  
Thoracic Esophagus ◽  
Spinal Neurons ◽  
Afferent Pathways ◽  
Dorsal Roots ◽  
Upper Cervical ◽  
Cervical Vagotomy ◽  
Bilateral Vagotomy ◽  
Extracellular Potentials ◽  
Stimulation Of

Because vagal and sympathetic inputs activate upper cervical spinal neurons, we hypothesized that stimulation of the esophagus would activate C1–C2 neurons. This study examined responses of C1–C2 spinal neurons to cervical and thoracic esophageal distension (CED, TED) and afferent pathways for CED and TED inputs to C1–C2 spinal neurons. Extracellular potentials of single C1–C2 spinal neurons were recorded in pentobarbital-anesthetized male rats. Graded CED or TED was produced by water inflation (0.1–0.5 ml) of a latex balloon. CED changed activity of 48/219 (22%) neurons; 34 were excited (E), 12 were inhibited (I), and 2 were E-I. CED elicited responses for 18/18 neurons tested after ipsilateral cervical vagotomy, for 12/14 neurons tested after bilateral vagotomy and for 9/11 neurons tested after bilateral vagotomy and C6–C7 spinal cord transection. TED changed activity of 31/190 (16%) neurons (28E, 3 I). Ipsilateral cervical vagotomy abolished TED-evoked responses of 5/12 neurons. Bilateral vagotomy eliminated responses of 2/4 neurons tested, and C6–C7 spinal transection plus bilateral vagotomy eliminated responses of 2/2 neurons. Thus inputs from CED to C1–C2 neurons most likely entered upper cervical dorsal roots, whereas inputs from TED were dependent on vagal pathways and/or sympathetic afferent pathways that entered the thoracic dorsal roots. These results supported a concept that C1–C2 spinal neurons play a role in integrating visceral information from cervical and thoracic esophagus.

Afferent pathways for cardiac-somatic motor reflexes in rats

2001 ◽  
Vol 281 (6) ◽  
pp. R2096-R2102 ◽  
Author(s):  
C. Jerry Jou ◽  
Jay P. Farber ◽  
Chao Qin ◽  
Robert D. Foreman
Keyword(s):  
Electrical Stimulation ◽  
Visceral Afferents ◽  
Emg Activity ◽  
Nerve Transection ◽  
Paraspinal Muscles ◽  
Afferent Pathways ◽  
Anginal Pain ◽  
Bilateral Vagotomy ◽  
Cardiac Afferents ◽  
Stimulation Of

The present study used a rat model in which algogenic chemicals were infused into the pericardial sac to evoke spasmlike contractions in paraspinal muscles. The following techniques were used to study the roles of sympathetic (SCA) and vagal cardiac afferents (VCA) in electromyographic (EMG) responses to pericardial algogenic chemicals: chemical stimulation, electrical stimulation, and nerve transection. Activation with bradykinin ( n = 46) produced a significantly higher peak response than infusion of an algogenic mixture ( n = 53) containing chemicals that also activate VCA. Electrical stimulation of SCA produced bilateral EMG activities (7 of 7). Electrical stimulation of VCA did not evoke EMG activity but inhibited the chemically evoked EMG response (12 of 12). The chemically evoked response was decreased after transection of the left sympathetic chain ( n = 22) and was increased after bilateral vagotomy ( n = 19). These results suggest an excitatory and inhibitory role for SCA and VCA, respectively. Therefore, in addition to spinothalamic convergence of somatic and visceral afferents, activation of SCA to generate spasmlike muscle contractions could account in part for anginal pain, and VCA activation could attenuate this effect.

Importance of vagal afferents in determining ventilation in newborn rats

1988 ◽  
Vol 65 (3) ◽  
pp. 1033-1039 ◽  
Author(s):  
L. Fedorko ◽  
E. N. Kelly ◽  
S. J. England
Keyword(s):  
Afferent Input ◽  
Vagal Afferents ◽  
Newborn Rats ◽  
Inspiratory Time ◽  
Adult Rats ◽  
Peripheral Chemoreceptor ◽  
Air Breathing ◽  
Ventilatory Pattern ◽  
Threefold Increase ◽  
Bilateral Vagotomy

We studied the effect of acute bilateral vagotomy on ventilation and ventilatory pattern in rats. In 1- to 6-day-old unanesthetized rats, vagotomy resulted in a substantial decrease (38%) in ventilation during air breathing. After vagotomy there was a threefold increase in tidal volume (VT), inspiratory time (TI) doubled, and expiratory time (TE) was six times longer. When studied under isoflurane anesthesia, newborn rats showed decreases in ventilation similar to that observed without anesthesia, whereas anesthetized adult rats had no consistent changes in ventilation. Adult and newborn rats had nearly identical proportionate increases in VT and TI after vagotomy, but TE lengthened to a greater extent in the newborns. Additionally, we demonstrated a significant decrease in ventilation when 100% O2 rather than air was supplied to nonvagotomized unanesthetized newborn rats. Ventilation decreased by 19% after vagotomy under hyperoxic conditions. We conclude that vagal afferent input, probably of pulmonary mechanoreceptor origin, provides positive feedback to respiration in newborn rats and that newborn rats greater than 24 h old also have a degree of peripheral chemoreceptor drive during air breathing.

Afferent input to movement-related precentral neurones in conscious monkeys

1976 ◽  
Vol 194 (1116) ◽  
pp. 313-339 ◽  
Keyword(s):  
Pyramidal Tract ◽  
Significant Proportion ◽  
Receptive Fields ◽  
Total Sample ◽  
Afferent Input ◽  
Peripheral Region ◽  
Joint Movement ◽  
Natural Stimulus ◽  
Natural Stimuli ◽  
Stimulation Of

Monkeys were trained to perform a stereotyped movement task, and to accept passive manipulation and natural stimulation of the limbs while remaining relaxed and quiet. All training, both of movement and for relaxation, was with food rewards. The effects of natural stimuli on 257 precentral neurones showing consistent modulations in discharge frequency during the performance of the movement task were investigated. Most precentral neurones had small, stable input zones located on the contralateral arm: 197 facilitatory and 17 inhibitory responses were obtained, while the remaining 43 cells were unaffected by the natural stimuli used. The most common natural stimulus capable of influencing precentral neurones was joint movement: 152 cells responded to joint movement, including 98 which only responded to movement at a single joint. Joint movement rather than joint position was the effective stimulus and none of these cells was influenced by palpation of muscles acting at the joint. The next most common natural stimulus capable of influencing precentral neurones was muscle palpation: 35 cells responded to a tap applied to a localized portion of the muscle belly, including 26 cells which also responded to movement of the joint at which the muscle acted. The direction of joint movement which influenced the cell was usually such as to stretch the muscle containing the receptors for the effective afferent input set up by tapping. The natural stimulus which influenced the smallest number of precentral neurones was tactile stimulation of the skin: 27 cells had cutaneous receptive fields, most of which were small ( < 5 cm 2 ) and confined to the hand. Included in the total sample were 51 pyramidal tract neurones. The behaviour of these was found to be similar to the unidentified neurones examined in the same animals with respect to their afferent input. However, there was a tendency for pyramidal tract neurones to be in receipt of a more convergent input than unidentified neurones in their vicinity. The majority of neurones recorded in close proximity to one another (within 500 μm or less) usually received their afferent input from the same peripheral region, but a significant proportion of such cells received inputs from different and remote peripheral zones. Hence the afferent input to the precentral motor cortex is not organized to provide independent and spatially segregated projections from particular peripheral sites only to limited and localized radial aggregations of neurones.

Response of Laryngeal Airway Resistance to Chemoreceptor Stimulation: Effect of Pulmonary Afferent Denervation

1982 ◽  
Vol 90 (6) ◽  
pp. 723-727
Author(s):  
Thomas V. McCaffrey
Keyword(s):  
Airway Resistance ◽  
Afferent Input ◽  
Respiratory Neurons ◽  
Vagus Nerves ◽  
Before And After ◽  
Bilateral Vagotomy ◽  
Recurrent Laryngeal Nerves ◽  
Laryngeal Resistance ◽  
Stimulation Of ◽  
Laryngeal Airway

The response of laryngeal airway resistance to chemoreceptor stimulation was measured before and after vagotomy in ten anesthetized dogs. With the vagus nerves intact, stimulation of chemoreceptors produced a decrease in both inspiratory and expiratory laryngeal resistance. After bilateral vagotomy below the origin of the recurrent laryngeal nerves, stimulation of chemoreceptors produced a smaller decrease in inspiratory laryngeal resistance and an increase in expiratory laryngeal resistance. We concluded that pulmonary afferent input to the respiratory neurons maintains a low airway resistance during chemoreceptor stimulation.

Epilepsy, Electroacupuncture and the Nucleus of the Solitary Tract

2006 ◽  
Vol 24 (4) ◽  
pp. 164-168 ◽  
Author(s):  
Yusuf Ozgur Cakmak
Keyword(s):  
Vagus Nerve ◽  
Nerve Stimulation ◽  
Vagal Afferents ◽  
Auricular Acupuncture ◽  
Acupuncture Points ◽  
Solitary Tract ◽  
Laboratory Findings ◽  
Afferent Pathways ◽  
The Brain ◽  
Stimulation Of

Vagal nerve stimulation and electroacupuncture have some promise as neuroprotective therapies for patients with poorly controlled epilepsy. It has been demonstrated that stimulation of acupuncture points on the extremities results in stimulation of the vagus nerve. It is possible that the antiepileptic effects of these two applications might be targeting the same centre in the brain. The nucleus of the solitary tract, which is a primary site at which vagal afferents terminate, is also the site for afferent pathways of facial, scalp and auricular acupuncture via trigeminal, cervical spinal and glossopharyngeal nerves. Taken together with laboratory findings, the neuroprotective pathways of electroacupuncture in epileptic models may stem from the collaboration of its anti-inflammatory and neurotrophic actions through the nucleus of the solitary tract via vagus nerve stimulation.

scholarly journals Stomach Region Stimulated Determines Effects on Duodenal Motility in Rats

2021 ◽  
Author(s):  
Zhenjun T TAN ◽  
Matthew Ward ◽  
Robert J Phillips ◽  
Xueguo Zhang ◽  
Deborah M Jaffey ◽  
...  
Keyword(s):  
Electrode Site ◽  
Vagal Afferents ◽  
Male Rats ◽  
Motor Responses ◽  
Duodenal Motility ◽  
Serosal Surface ◽  
Stretch Receptors ◽  
Excitatory Responses ◽  
Post Hoc ◽  
Stimulation Of

Gastric electrical stimulation (GES) is used clinically to promote proximal GI emptying and motility. In acute experiments, we measured duodenal motor responses elicited by GES applied at 141 randomly chosen electrode sites on the stomach serosal surface. Overnight-fasted (H2O available) anesthetized male rats (n = 81) received intermittent biphasic GES for 5 min (20s-on/40s-off cycles; I = 0.3mA; pw = 0.2ms; 10 Hz). A strain gauge on the serosal surface of the proximal duodenum of each animal was used to evaluate baseline motor activity and the effect of GES. Using ratios of time blocks compared to a 15-min pre-stimulation baseline, we evaluated the effects of the 5-min stimulation on concurrent activity; on the 10-min immediately after the stimulation, and on the 15-min period beginning with the onset of stimulation. We mapped the magnitude of the duodenal response (3 different motility indices) elicited from the 141 stomach sites. Post hoc electrode site maps associated with duodenal responses suggested three zones similar to the classic regions of forestomach, corpus and antrum. Maximal excitatory duodenal motor responses were elicited from forestomach sites, whereas inhibitory responses occurred with stimulation of the corpus. Moderate excitatory duodenal responses occurred with stimulation of the antrum. Complex, weak inhibitory/excitatory responses were produced by stimulation at boundaries between stomach regions. Patterns of GES efficacies coincided with distributions of previously mapped vagal afferents, suggesting that excitation of the duodenum is strongest when GES electrodes are situated over stomach concentrations of vagal intramuscular arrays, putative stretch receptors in the muscle wall.

Inhalation of a pulmonary irritant modulates activity of lumbosacral spinal neurons receiving colonic input in rats

2007 ◽  
Vol 293 (5) ◽  
pp. R2052-R2058 ◽  
Author(s):  
Chao Qin ◽  
Robert D. Foreman ◽  
Jay P. Farber
Keyword(s):  
Afferent Input ◽  
Male Rats ◽  
Ammonia Vapor ◽  
Spinal Neurons ◽  
Afferent Fibers ◽  
Cervical Vagotomy ◽  
Nociceptive Pathway ◽  
Lower Airways ◽  
Increased Activity ◽  
Extracellular Potentials

The purpose of the present study was to determine whether an intraspinal nociceptive pathway from the lungs modulated activity of spinal neurons that also received afferent input from the colon. Extracellular potentials of single lumbosacral (L6–S2) spinal neurons were recorded in pentobarbital-anesthetized, paralyzed, and ventilated male rats. The lower airways and lungs were irritated by injecting ammonia vapor over a 30% NH4OH solution into the inspiratory line of the ventilator (0.5 ml, 20 s). Graded colorectal distension (CRD; 20–60 mmHg, 20 s) was produced by air inflation of a balloon. Inhaled ammonia (IA) altered activity of 31/51 (61%) lumbosacral spinal neurons responding to noxious CRD (60 mmHg, 20 s). In contrast, IA changed activity of 3/30 (10%) spinal neurons with somatic fields that did not respond to colorectal inputs. IA decreased activity of 16/31 (52%) spinal neurons and increased activity of the other 15 neurons with colorectal input. Multiple patterns of viscerovisceral convergent spinal neurons with excitatory and inhibitory responses to CRD and IA were observed; 87% (27/31) of the viscerovisceral convergent neurons also responded to innocuous and/or noxious stimuli of somatic fields. Bilateral cervical vagotomy abolished responses to IA in 2/8 tested neurons, indicating that the remaining 6 neurons had input originating from sympathetic afferent fibers. Rostral C1 spinal transection did not abolish inhibitory responses to IA in 4/4 neurons, but L2 transection eliminated inhibitory responses to IA in 3/3 neurons. These results indicated that irritation of the lower airways modulated activity of lumbosacral spinal neurons with colorectal input. It might contribute to intraspinal cross talk between the colon and lungs.

Interactions between sympathetic and vagal cardiac afferents in nucleus tractus solitarii

1997 ◽  
Vol 272 (6) ◽  
pp. H2843-H2851 ◽  
Author(s):  
S. Tjen-A-Looi ◽  
A. Bonham ◽  
J. Longhurst
Keyword(s):  
Unit Activity ◽  
Pressor Response ◽  
Nucleus Tractus Solitarii ◽  
Vagal Afferents ◽  
Afferent Pathways ◽  
Before And After ◽  
The Central Nervous System ◽  
Afferent Inputs ◽  
Cardiac Afferents ◽  
Alpha Chloralose

Epicardial application of hydrogen peroxide (H2O2) reflexly elicits a sympathetically mediated pressor response. This pressor response is augmented by vagotomy and abolished by sympathectomy, suggesting an occlusive interaction between the afferents in the central nervous system (CNS). To support this observation we recorded sympathetic efferent responses from the sympathetic chain (T1-T2) before and after epicardial application of H2O2 in six cats before and after vagotomy. Cardiac sympathetic efferent responses to H2O2 were increased by vagotomy. Thus there exists an occlusive interaction between the two afferent pathways in the CNS. Because cardiopulmonary vagal afferents make their first central synapse in the nucleus tractus solitarii (NTS), we further hypothesized that cells in the NTS receive convergent inputs from sympathetic and vagal afferents and that the inputs would interact in an occlusive manner. In alpha-chloralose-anesthetized sinoaortic-denervated cats, cardiac sympathetic and vagal branches were stimulated electrically at 1 Hz, either separately or in combination. Extracellular single-unit activity was recorded in the NTS. Vagal stimuli most frequently (38%) diminished sympathetically evoked unit activity (-46.6 +/- 6.0%) versus control (1.4 +/- 1.5%). However, a few (21%) vagal and sympathetic afferent inputs were found to be additive or facilitative. We conclude that interactions occur between cardiac sympathetic and vagal afferents in the NTS. It is possible that this occlusive interaction explains the alteration in cardiac sympathetic outflow after epicardial stimulation with H2O2.

Role of chemical afferents in the maintenance of rhythmic respiratory movements

1983 ◽  
Vol 54 (2) ◽  
pp. 453-459 ◽  
Author(s):  
W. R. See ◽  
M. E. Schlaefke ◽  
H. H. Loeschcke
Keyword(s):  
Respiratory Rhythm ◽  
Afferent Input ◽  
Vagal Afferents ◽  
Peripheral Chemoreceptors ◽  
Central Chemosensitivity ◽  
Relative Contribution ◽  
Ventilatory Drive ◽  
Respiratory Movements ◽  
Stimulation Of

In seven anesthetized cats central chemosensitivity was eliminated (cold block) and peripheral chemoreceptors were either stimulated or eliminated (sectioned) to test whether nonchemical vagal afferents can maintain rhythmic ventilation and to determine the relative contribution of the carotid and aortic chemoreceptors to ventilatory drive without central chemosensitivity. Elimination of all chemical afferents invariably induced apnea, whereas ventilation was reduced from 533 to 159 ml X min-1 during cold block of central chemosensitivity and to 478 ml X min-1 after sectioning both sinus nerves. Cold block with only the aortic chemoreceptors and vagal afferents intact produced apnea in four of six cases tested. Stimulation of peripheral chemoreceptors during cold block remained effective and interrupted apnea in three of the four cats with only aortic chemoreceptors intact. We conclude that the nonchemical vagal respiratory afferents alone are unable to maintain rhythmic ventilation. Respiratory rhythm generation is, under the conditions of our experiments, critically dependent on sufficient afferent input from chemical afferents. Of these, central chemosensitivity plays the major role, followed by carotid body and, least importantly, by aortic afferents.

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