scholarly journals An objective approach to assess colonic pain in mice using colonometry

PLoS ONE ◽  
2021 ◽  
Vol 16 (3) ◽  
pp. e0245410
Author(s):  
Liya Y. Qiao ◽  
Jonathan Madar
Keyword(s):  
Neurological Disorders ◽  
Stretch Reflex ◽  
Distal Colon ◽  
Saline Infusion ◽  
Noxious Stimulation ◽  
Trinitrobenzene Sulfonic Acid ◽  
Primary Afferent ◽  
Reflex Pathways ◽  
Constant Rate ◽  
Stimulation Of

The present study presents a non-surgical approach to assess colonic mechanical sensitivity in mice using colonometry, a technique in which colonic stretch-reflex contractions are measured by recording intracolonic pressures during saline infusion into the distal colon in a constant rate. Colonometrical recording has been used to assess colonic function in healthy individuals and patients with neurological disorders. Here we found that colonometry can also be implemented in mice, with an optimal saline infusion rate of 1.2 mL/h. Colonometrograms showed intermittent pressure rises that was caused by periodical colonic contractions. In the sceneries of colonic hypersensitivity that was generated post 2,4,6-trinitrobenzene sulfonic acid (TNBS)-induced colonic inflammation, following chemogenetic activation of primary afferent neurons, or immediately after noxious stimulation of the colon by colorectal distension (CRD), the amplitude of intracolonic pressure (AICP) was markedly elevated which was accompanied by a faster pressure rising (ΔP/Δt). Colonic hypersensitivity-associated AICP elevation was a result of the enhanced strength of colonic stretch-reflex contraction which reflected the heightened activity of the colonic sensory reflex pathways. The increased value of ΔP/Δt in colonic hypersensitivity indicated a lower threshold of colonic mechanical sensation by which colonic stretch-reflex contraction was elicited by a smaller saline infusion volume during a shorter period of infusion time. Chemogenetic inhibition of primary afferent pathway that was governed by Nav1.8-expressing cells attenuated TNBS-induced up-regulations of AICP, ΔP/Δt, and colonic pain behavior in response to CRD. These findings support that colonometrograms can be used for analysis of colonic pain in mice.

scholarly journals An objective approach to assess colonic pain in mice using colonometry

2020 ◽  
Author(s):  
Liya Y Qiao ◽  
Jonathan Madar
Keyword(s):  
Neurological Disorders ◽  
Stretch Reflex ◽  
Distal Colon ◽  
Saline Infusion ◽  
Noxious Stimulation ◽  
Trinitrobenzene Sulfonic Acid ◽  
Primary Afferent ◽  
Reflex Pathways ◽  
Constant Rate ◽  
Stimulation Of

ABSTRACTThe present study presents a non-surgical approach to assess colonic mechanical sensitivity in mice using colonometry, a technique in which colonic stretch-reflex contractions are measured by recording intracolonic pressures during saline infusion into the distal colon in a constant rate. Colonometrical recording has been used to assess colonic function in healthy individuals and patients with neurological disorders. Here we found that colonometry can also be implemented in mice, with an optimal saline infusion rate of 1.2 mL/h. Colonometrograms showed intermittent pressure rises that was caused by periodical colonic contractions. In the sceneries of colonic hypersensitivity that was generated post 2,4,6-trinitrobenzene sulfonic acid (TNBS)-induced colonic inflammation, following chemogenetic activation of primary afferent neurons, or immediately after noxious stimulation of the colon by colorectal distension (CRD), the amplitude of intracolonic pressure (AICP) was markedly elevated which was accompanied by a faster pressure rising (ΔP/Δt). Colonic hypersensitivity-associated AICP elevation was a result of the enhanced strength of colonic stretch-reflex contraction which reflected the heightened activity of the colonic sensory reflex pathways. The increased value of ΔP/Δt in colonic hypersensitivity indicated a lower threshold of colonic mechanical sensation by which colonic stretch-reflex contraction was elicited by a smaller saline infusion volume during a shorter period of infusion time. Chemogenetic inhibition of primary afferent pathway that was governed by Nav1.8-expressing cells attenuated TNBS-induced up-regulations of AICP, ΔP/Δt, and colonic pain behavior in response to CRD. These findings support that colonometrograms can be used for analysis of colonic pain in mice.

scholarly journals POST-TETANIC POTENTIATION OF POLYSYNAPTIC REFLEXES OF THE SPINAL CORD

1955 ◽  
Vol 39 (2) ◽  
pp. 197-206 ◽  
Author(s):  
Victor J. Wilson
Keyword(s):  
Spinal Cord ◽  
Time Course ◽  
Monosynaptic Reflex ◽  
Primary Afferent ◽  
Reflex Pathways ◽  
Post Tetanic Potentiation ◽  
Reflex Discharge ◽  
Polysynaptic Reflexes ◽  
Afferent Terminals ◽  
Stimulation Of

The phenomenon of post-tetanic potentiation has been studied in the cat spinal cord with particular reference to polysynaptic responses. Following tetanization of dorsal roots, these reflexes show an increased response, as measured in terms of their voltage-time area, with a predominant change in the earlier reflex pathways. Both of these changes in the reflex discharge have a time course of 15 to 25 seconds. Post-tetanic potentiation is also observed in response to stimulation of a dorsal rootlet following tetanization of another rootlet in the same or in a neighboring segment. This effect can be explained by post-tetanic changes in the terminals of secondary, and possibly higher order, internuncial cells, essentially similar to those changes in the primary afferent terminals which give rise to potentiation of the monosynaptic reflex.

Drastic Decrease in Isoflurane Minimum Alveolar Concentration and Limb Movement Forces after Thoracic Spinal Cooling and Chronic Spinal Transection in Rats

2005 ◽  
Vol 102 (3) ◽  
pp. 624-632 ◽  
Author(s):  
Steven L. Jinks ◽  
Carmen L. Dominguez ◽  
Joseph F. Antognini
Keyword(s):  
Spinal Cord ◽  
Spinal Cord Injury ◽  
Minimum Alveolar Concentration ◽  
Tail Flick ◽  
Noxious Stimulation ◽  
Partial Recovery ◽  
Spinal Transection ◽  
Thoracic Spinal ◽  
Cord Injury ◽  
Stimulation Of

Background Individuals with spinal cord injury may undergo multiple surgical procedures; however, it is not clear how spinal cord injury affects anesthetic requirements and movement force under anesthesia during both acute and chronic stages of the injury. Methods The authors determined the isoflurane minimum alveolar concentration (MAC) necessary to block movement in response to supramaximal noxious stimulation, as well as tail-flick and hind paw withdrawal latencies, before and up to 28 days after thoracic spinal transection. Tail-flick and hind paw withdrawal latencies were measured in the awake state to test for the presence of spinal shock or hyperreflexia. The authors measured limb forces elicited by noxious mechanical stimulation of a paw or the tail at 28 days after transection. Limb force experiments were also conducted in other animals that received a reversible spinal conduction block by cooling the spinal cord at the level of the eighth thoracic vertebra. Results A large decrease in MAC (to </= 40% of pretransection values) occurred after spinal transection, with partial recovery (to approximately 60% of control) at 14-28 days after transection. Awake tail-flick and hind paw withdrawal latencies were facilitated or unchanged, whereas reflex latencies under isoflurane were depressed or absent. However, at 80-90% of MAC, noxious stimulation of the hind paw elicited ipsilateral limb withdrawals in all animals. Hind limb forces were reduced (by >/= 90%) in both chronic and acute cold-block spinal animals. Conclusions The immobilizing potency of isoflurane increases substantially after spinal transection, despite the absence of a baseline motor depression, or "spinal shock." Therefore, isoflurane MAC is determined by a spinal depressant action, possibly counteracted by a supraspinal facilitatory action. The partial recovery in MAC at later time points suggests that neuronal plasticity after spinal cord injury influences anesthetic requirements.

Defecation Induced by Stimulation of Sacral S2 Spinal Root in Cats

2021 ◽  
Author(s):  
Jicheng Wang ◽  
Zhijun Shen ◽  
Bing Shen ◽  
Jianan Jian ◽  
Travis Hannan ◽  
...  
Keyword(s):  
Distal Colon ◽  
Spinal Nerve ◽  
Ventral Root ◽  
Spinal Root ◽  
Balloon Catheters ◽  
Minimally Invasive Surgical ◽  
Lead Electrode ◽  
Cord Injury ◽  
Minute Duration ◽  
Stimulation Of

The aim of this study was to determine if stimulation of sacral spinal nerve roots can induce defecation in cats. In anesthetized cats, bipolar hook electrodes were placed on the S1-S3 dorsal and/or ventral roots. Stimulus pulses (1-50 Hz, 0.2 ms) were applied to an individual S1-S3 root to induce proximal/distal colon contractions and defecation. Balloon catheters were inserted into the proximal and distal colon to measure contraction pressure. Glass marbles were inserted into the rectum to demonstrate defecation by videotaping the elimination of marbles. Stimulation of the S2 ventral root at 7 Hz induced significantly (p<0.05) larger contractions (32±9 cmH2O) in both proximal and distal colon than stimulation of the S1 or S3 ventral root. Intermittent (5 times) stimulation (1 minute on and 1 minute off) of both dorsal and ventral S2 roots at 7 Hz produced reproducible colon contractions without fatigue, while continuous stimulation of 5-minute duration caused significant fatigue in colon contractions. Stimulation (7 Hz) of both dorsal and ventral S2 roots together successfully induced defecation that eliminated 1-2 marbles from the rectum. This study indicates the possibility to develop a novel neuromodulation device to restore defecation function after spinal cord injury using a minimally invasive surgical approach to insert a lead electrode via the sacral foramen to stimulate a sacral spinal root.

Excitability of primary afferents in feline spinal cord: taurine, homotaurine, and γ-aminobutyric acid compared

1982 ◽  
Vol 60 (6) ◽  
pp. 850-855 ◽  
Author(s):  
Radan Čapek ◽  
Barbara Esplin
Keyword(s):  
Primary Afferents ◽  
Aminobutyric Acid ◽  
Primary Afferent Depolarization ◽  
Conditioning Stimulation ◽  
Primary Afferent ◽  
Antagonistic Muscle ◽  
Consistent Change ◽  
Muscle Nerve ◽  
Gaba Synthesis ◽  
Stimulation Of

Effects of taurine and homotaurine (3-aminopropancsuIfonic acid), on excitability of primary afferents were compared with effects of γ-aminobutyric acid (GABA) in spinal unanaesthesized cats. Homotaurine and GABA, administered intravenously or topically, produced a marked increase in afferent excitability. Homotaurine was about 10 times more potent than GABA. Taurine (up to 2 mmol/kg i.v., or 10 mM topically) did not produce a consistent change in afferent excitability. The effect of homotaurine was antagonized by bicuculline or picrotoxin in doses which suppressed the primary afferent depolarization, as indicated by an increase of afferent excitability, evoked by conditioning stimulation of an antagonistic muscle nerve. Semicarbazidc, an inhibitor of GABA synthesis, did not attenuate the homotaurine-induced excitability changes of afferents while suppressing entirely the primary afferent depolarization. These findings suggest that homotaurine exerts a direct GABA-like action on feline primary afferents.

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