scholarly journals Spinal Anesthesia Reduces Myocardial Ischemia–triggered Ventricular Arrhythmias by Suppressing Spinal Cord Neuronal Network Interactions in Pigs

2021 ◽  
Vol 134 (3) ◽  
pp. 405-420
Author(s):  
Yukiko Omura ◽  
Jasmine P. Kipke ◽  
Siamak Salavatian ◽  
Andrew Shea Afyouni ◽  
Christian Wooten ◽  
...  
Keyword(s):  
Spinal Cord ◽  
Myocardial Ischemia ◽  
Spinal Anesthesia ◽  
Dorsal Horn ◽  
Ventricular Arrhythmias ◽  
Spinal Reflexes ◽  
Spinal Cord Dorsal Horn ◽  
Short Term ◽  
Intermediolateral Nucleus ◽  
Ventricular Arrhythmogenesis

Background Cardiac sympathoexcitation leads to ventricular arrhythmias. Spinal anesthesia modulates sympathetic output and can be cardioprotective. However, its effect on the cardio-spinal reflexes and network interactions in the dorsal horn cardiac afferent neurons and the intermediolateral nucleus sympathetic neurons that regulate sympathetic output is not known. The authors hypothesize that spinal bupivacaine reduces cardiac neuronal firing and network interactions in the dorsal horn–dorsal horn and dorsal horn–intermediolateral nucleus that produce sympathoexcitation during myocardial ischemia, attenuating ventricular arrhythmogenesis. Methods Extracellular neuronal signals from the dorsal horn and intermediolateral nucleus neurons were simultaneously recorded in Yorkshire pigs (n = 9) using a 64-channel high-density penetrating microarray electrode inserted at the T2 spinal cord. Dorsal horn and intermediolateral nucleus neural interactions and known markers of cardiac arrhythmogenesis were evaluated during myocardial ischemia and cardiac load–dependent perturbations with intrathecal bupivacaine. Results Cardiac spinal neurons were identified based on their response to myocardial ischemia and cardiac load–dependent perturbations. Spinal bupivacaine did not change the basal activity of cardiac neurons in the dorsal horn or intermediolateral nucleus. After bupivacaine administration, the percentage of cardiac neurons that increased their activity in response to myocardial ischemia was decreased. Myocardial ischemia and cardiac load–dependent stress increased the short-term interactions between the dorsal horn and dorsal horn (324 to 931 correlated pairs out of 1,189 pairs, P < 0.0001), and dorsal horn and intermediolateral nucleus neurons (11 to 69 correlated pairs out of 1,135 pairs, P < 0.0001). Bupivacaine reduced this network response and augmentation in the interactions between dorsal horn–dorsal horn (931 to 38 correlated pairs out of 1,189 pairs, P < 0.0001) and intermediolateral nucleus–dorsal horn neurons (69 to 1 correlated pairs out of 1,135 pairs, P < 0.0001). Spinal bupivacaine reduced shortening of ventricular activation recovery interval and dispersion of repolarization, with decreased ventricular arrhythmogenesis during acute ischemia. Conclusions Spinal anesthesia reduces network interactions between dorsal horn–dorsal horn and dorsal horn–intermediolateral nucleus cardiac neurons in the spinal cord during myocardial ischemia. Blocking short-term coordination between local afferent–efferent cardiac neurons in the spinal cord contributes to a decrease in cardiac sympathoexcitation and reduction of ventricular arrhythmogenesis. Editor’s Perspective What We Already Know about This Topic What This Article Tells Us That Is New

Electrical Stimulation of the Anterior Cingulate Cortex Reduces Responses of Rat Dorsal Horn Neurons to Mechanical Stimuli

2005 ◽  
Vol 94 (1) ◽  
pp. 845-851 ◽  
Author(s):  
Arun K. Senapati ◽  
Stacey C. Lagraize ◽  
Paula J. Huntington ◽  
Hilary D. Wilson ◽  
Perry N. Fuchs ◽  
...  
Keyword(s):  
Spinal Cord ◽  
Dorsal Horn ◽  
Anterior Cingulate ◽  
Spinal Cord Dorsal Horn ◽  
Mechanical Stimuli ◽  
Short Term ◽  
Dorsal Horn Neurons ◽  
Spinal Cord Dorsal ◽  
Stimulation Of

The anterior cingulate cortex (ACC) is involved in the affective and motivational aspect of pain perception. Behavioral studies show a decreased avoidance behavior to noxious stimuli without change in mechanical threshold after stimulation of the ACC. However, as part of the neural circuitry of behavioral reflexes, there is no evidence showing that ACC stimulation alters dorsal horn neuronal responses. We hypothesize that ACC stimulation has two phases: a short-term phase in which stimulation elicits antinociception and a long-term phase that follows stimulation to change the affective response to noxious input. To begin testing this hypothesis, the purpose of this study was to examine the response of spinal cord dorsal horn neurons during stimulation of the ACC. Fifty-eight wide dynamic range spinal cord dorsal horn neurons from adult Sprague-Dawley rats were recorded in response to graded mechanical stimuli (brush, pressure, and pinch) at their respective receptive fields, while simultaneous stepwise electrical stimulations (300 Hz, 0.1 ms, at 10, 20, and 30 V) were applied in the ACC. The responses to brush at control, 10, 20, and 30 V, and recovery were 14.2 ± 1.4, 12.3 ± 1.2, 10.9 ± 1.2, 10.3 ± 1.1, and 14.1 ± 1.4 spikes/s, respectively. The responses to pressure at control, 10, 20, and 30 V, and recovery were 39.8 ± 4.7, 25.6 ± 3.0, 25.0 ± 3.0, 21.6 ± 2.4, and 34.2 ± 3.7 spikes/s, respectively. The responses to pinch at control, 10, 20, and 30 V, and recovery were 40.7 ± 3.8, 30.6 ± 3.1, 27.8 ± 2.8, 27.2 ± 3.2, and 37.4 ± 3.9 spikes/s, respectively. We conclude that electrical stimulation of the ACC induces significant inhibition of the responses of spinal cord dorsal horn neurons to noxious mechanical stimuli. The stimulation-induced inhibition begins to recover as soon as the stimulation is terminated. These results suggest differential short-term and long-term modulatory effects of the ACC stimulation on nociceptive circuits.

scholarly journals Delta Opioid Receptors Presynaptically Regulate Cutaneous Mechanosensory Neuron Input to the Spinal Cord Dorsal Horn

Neuron ◽  
2014 ◽  
Vol 81 (6) ◽  
pp. 1443 ◽  
Author(s):  
Rita Bardoni ◽  
Vivianne L. Tawfik ◽  
Dong Wang ◽  
Amaury François ◽  
Carlos Solorzano ◽  
...  
Keyword(s):  
Spinal Cord ◽  
Dorsal Horn ◽  
Opioid Receptors ◽  
Spinal Cord Dorsal Horn ◽  
Mechanosensory Neuron ◽  
Delta Opioid Receptors ◽  
Spinal Cord Dorsal

Distribution of substance P in the spinal cord of patients with syringomyelia

1996 ◽  
Vol 84 (6) ◽  
pp. 992-998 ◽  
Author(s):  
Thomas H. Milhorat ◽  
Harrison T. M. Mu ◽  
Carole C. LaMotte ◽  
Ade T. Milhorat
Keyword(s):  
Spinal Cord ◽  
Substance P ◽  
Dorsal Horn ◽  
Ventral Horn ◽  
Immunohistochemical Method ◽  
Positive Staining ◽  
Content Type ◽  
Normal Individuals ◽  
Neurologically Normal ◽  
Intermediolateral Nucleus

✓ The distribution of substance P, a putative neurotransmitter and pain-related peptide, was studied using the peroxidase—antiperoxidase immunohistochemical method in the spinal cords obtained from autopsy of 10 patients with syringomyelia and 10 age- and sex-matched, neurologically normal individuals. Substance P immunoreactivity was present in axons and in terminal-like processes in close apposition to neurons in the first, second, and third laminae of the dorsal horn. Smaller amounts of peroxidase-positive staining were found in the fifth lamina of the dorsal horn, the intermediolateral nucleus, the intermediomedial nucleus, and the ventral horn. In nine of 10 patients with syringomyelia, there was a substantial increase in substance P immunoreactivity in the first, second, third, and fifth laminae below the level of the lesion. A marked reduction or absence of staining was present in segments of the spinal cord occupied by the syrinx. Central cavities produced bilateral abnormalities, whereas eccentric cavities produced changes that were ipsilateral to the lesion. No alterations in staining were found in the spinal cord of an asymptomatic patient with a small central syrinx. The authors conclude that syringomyelia can be associated with abnormalities in spinal cord levels of substance P, which may affect the modulation and perception of pain.

scholarly journals Intrathecal Injection of the ς1Receptor Antagonist BD1047 Blocks Both Mechanical Allodynia and Increases in Spinal NR1 Expression during the Induction Phase of Rodent Neuropathic Pain

2008 ◽  
Vol 109 (5) ◽  
pp. 879-889 ◽  
Author(s):  
Dae-Hyun Roh ◽  
Hyun-Woo Kim ◽  
Seo-Yeon Yoon ◽  
Hyoung-Sig Seo ◽  
Young-Bae Kwon ◽  
...  
Keyword(s):  
Spinal Cord ◽  
Neuropathic Pain ◽  
Dorsal Horn ◽  
Mechanical Allodynia ◽  
Maintenance Phase ◽  
Spinal Cord Dorsal Horn ◽  
Induction Phase ◽  
Receptor Subunit ◽  
Aspartate Receptor ◽  
Spinal Cord Dorsal

Background Selective blockade of spinal sigma(1) receptors (Sig-1R) suppresses nociceptive behaviors in the mouse formalin test. The current study was designed to verify whether intrathecal Sig-1R antagonists can also suppress chronic neuropathic pain. Methods Neuropathic pain was produced by chronic constriction injury (CCI) of the right sciatic nerve in rats. The Sig-1R antagonist BD1047 was administered intrathecally twice daily from postoperative days 0 to 5 (induction phase of neuropathic pain) or from days 15 to 20 (maintenance phase). Western blot and immunohistochemistry were performed to determine changes in Sig-1R expression and to examine the effect of BD1047 on N-methyl-D-aspartate receptor subunit 1 expression and phosphorylation in spinal cord dorsal horn from neuropathic rats. Results BD1047 administered on postoperative days 0-5 significantly attenuated CCI-induced mechanical allodynia, but not thermal hyperalgesia, and this suppression was blocked by intrathecal administration of the Sig-1R agonist PRE084. In contrast, BD1047 treatment during the maintenance phase of neuropathic pain had no effect on mechanical allodynia. Sig-1R expression significantly increased in the ipsilateral spinal cord dorsal horn from days 1 to 3 after CCI. Importantly, BD1047 (30 nmol) administered intrathecally during the induction, but not the maintenance phase, blocked the CCI-induced increase in N-methyl-D-aspartate receptor subunit 1 expression and phosphorylation. Conclusions These results demonstrate that spinal Sig-1Rs play a critical role in both the induction of mechanical allodynia and the activation of spinal N-methyl-d-aspartate receptors in CCI rats and suggest a potential therapeutic role for the use of Sig-1R antagonists in the clinical management of neuropathic pain.

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