Sodium Channel Blockers Alter Slow-Wave Frequency of the Rat Stomach in vivo

Bielefeldt, Klaus; Bass, Paul

doi:10.1159/000200662

Cited by 8 publications

(7 citation statements)

References 19 publications

(30 reference statements)

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“…Another sodium channel blocker, mexiletine, effectively blocked inward sodium current responsible for depolwization of the cardiac action potentids (Yatani and Akaike 1985;Hering et al 1983). In the gastrointestinal tract, an in viva investigation r e v d d that mexiletine reduced gastric, but not Jejunal, slow wave frequency (Bielefeldt and Bass 1991). In the rnouse s d l intestine we observed that mexiletine did not alter the slow wave.…”

Section: Effwts Of Npg Flolfenmic Acid and Gadoliniummentioning

confidence: 49%

Generation of slow wave type action potentials in the mouse small intestine involves a non-L-type calcium channel

Malysz

Richardson²,

Farraway³

et al. 1995

Can. J. Physiol. Pharmacol.

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Intrinsic electrical activities in various isolated segments of the mouse small intestine were recorded (i) to characterize action potential generation and (ii) to obtain a profile on the ion channels involved in initiating the slow wave type action potentials (slow waves). Gradients in slow wave frequency, resting membrane potential, and occurrence of spiking activity were found, with the proximal intestine exhibiting the highest frequency, the most hyperpolarized cell membrane, and the greatest occurrence of spikes. The slow waves were only partially sensitive to L-type calcium channel blockers. Nifedipine, verapamil, and pinaverium bromide abolished spikes that occurred on the plateau phase of the slow waves in all tissues. The activity that remained in the presence of L-type calcium channel blockers, the upstroke potential, retained a similar amplitude to the original slow wave and was of identical frequency. The upstroke potential was not sensitive to a reduction in extracellular chloride or to the sodium channel blockers tetrodotoxin and mexiletine. Abolishment of the Na+ gradient by removal of 120 mM extracellular Na+ reduced the upstroke potential frequency by 13 - 18% and its amplitude by 50 - 70% in the ileum. The amplitude was similarly reduced by Ni2+ (up to 5 mM), and by flufenamic acid (100 mu M), a nonspecific cation and chloride channel blocker. Gadolinium, a nonspecific blocker of cation and stretch-activated channels, had no effect. Throughout these pharmacological manipulations, a robust oscillation remained at 5 - 10 mV. This oscillation likely reflects pacemaker activity. It was rapidly abolished by removal of extracellular calcium but not affected by L-type calcium channel blockers. In summary, the mouse small intestine has been established as a model for research into slow wave generation and electrical pacemaker activity. The upstroke part of the slow wave has two components, the pacemaker component involves a non-L-type calcium channel.

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Section: Effwts Of Npg Flolfenmic Acid and Gadoliniummentioning

confidence: 49%

Generation of slow wave type action potentials in the mouse small intestine involves a non-L-type calcium channel

Malysz

Richardson²,

Farraway³

et al. 1995

Can. J. Physiol. Pharmacol.

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“…RR were resampled and interpolated at a rate of 64 Hz to provide continuity in the time domain. Raw tracings of EGMG activity were inspected visually to verify the presence of gastric slow wave and to determine its frequency by calculating the number of slow wave activity during a random 10‐min period in each sleep–wake state (Bielefeldt and Bass, 1991). The provisional slow wave frequency was used as a reference in defining the EGMG frequency during subsequent power spectral analysis.…”

Section: Methodsmentioning

confidence: 99%

Involvement of sympathetic function in the sleep-related change of gastric myoelectrical activity in rats

Huang

Yang²,

Lai

et al. 2010

Journal of Sleep Research

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SUMMARYThe gastric myoelectrical activity (GMA) fluctuates across sleep-wake states as a result of modulation by the brain-gut axis. The role of the autonomic nervous system in this phenomenon, however, was not elucidated fully. Through simultaneous recording and subsequent continuous power spectral analysis of electroencephalogram, electromyogram, electrocardiogram and electrogastromyogram (EGMG) in 16 freely moving Wistar rats, the sleep-wake states of the animals were defined and indices of cardiac autonomic regulation and GMA were calculated. We found that both cardiac autonomic regulation and GMA fluctuated through sleep-wake cycles. Correlation analysis further revealed significant correlations between EGMG power and each of the R-R interval, high-frequency power, low-frequency power, very-low-frequency power, low-frequency power to high-frequency power ratio and normalized low-frequency power of heart rate variability with respect to their trend of change across different sleep-wake states. These results suggest that the sleep-wake-related change of GMA was related to sympathovagal balance. The sympathetic nerve may play a more important role in the central modulation of GMA than perceived previously.k e y w o r d s brain-gut axis, gastric myoelectrical activity, heart rate variability, rat, sleep

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“…This suggests that there is baseline flow of Na + through Na v 1.5 and that this flow is altered by mechanical forces applied to the cells that express Na v 1.5 whether in the human gut or heart. The Na + channel blockers decrease gastric slow wave frequency in vivo in unanaesthetized rats 50 . Pharmacological blockade of the Na + current in intestinal muscle strips decreases slow wave frequency and hyperpolarizes smooth muscle.…”

Section: Calcium Channelsmentioning

confidence: 99%

Mechanosensitive ion channels in interstitial cells of Cajal and smooth muscle of the gastrointestinal tract

Kraichely

Farrugia

2007

Neurogastroenterology Motil

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Normal gastrointestinal (GI) motility is required to mix digestive enzymes and food and to move content along the GI tract. Underlying the complex motor patterns of the gut are electrical events that reflect ion flux across cell membranes. Smooth muscle electrical activity is directly influenced by GI interstitial cells of Cajal, whose rhythmic oscillations in membrane potential in part determine the excitability of GI smooth muscle and its response to neuronal input. Coordinated activity of the ion channels responsible for the conductances that underlie ion flux in both smooth muscle and interstitial cells is a requisite for normal motility. These conductances are regulated by many factors, including mechanical stress. Recent studies have revealed mechanosensitivity at the level of the ion channels, and the mechanosensor within the channel has been identified in many cases. This has led to better comprehension of the role of mechanosensitive conductances in normal physiology and will undoubtedly lead to understanding of the consequences of disturbances in these conductances.

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Sodium Channel Blockers Alter Slow-Wave Frequency of the Rat Stomach in vivo

Cited by 8 publications

References 19 publications

Generation of slow wave type action potentials in the mouse small intestine involves a non-L-type calcium channel

Generation of slow wave type action potentials in the mouse small intestine involves a non-L-type calcium channel

Involvement of sympathetic function in the sleep-related change of gastric myoelectrical activity in rats

Mechanosensitive ion channels in interstitial cells of Cajal and smooth muscle of the gastrointestinal tract

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