Electromyography of the Stomach and Small-Intestine of the Tammar Wallaby, Macropus-Eugenii, and the Quokka, Setonix-Brachyurus

1988 ◽  
Vol 36 (4) ◽  
pp. 363 ◽  
Author(s):  
KC Richardson ◽  
RS Wyburn
Keyword(s):  
Small Intestine ◽  
Action Potential ◽  
Slow Wave ◽  
Action Potentials ◽  
Tammar Wallaby ◽  
Electromyographic Activity ◽  
Bipolar Electrodes ◽  
Macropus Eugenii ◽  
Potential Activity ◽  
Frequency Gradient

Electromyographic activity recorded by chronically implanted bipolar electrodes showed the tammar wallaby (Macropus eugenii) and the quokka (Setonix brachyurus) to have slow wave activity over the entire stomach and small intestine. Slow wave mean frequency (min-') were: 5.5 and 5.3 for the forestomach; 5.4 and 5.0 for the pylorus; 26 and 17.8 for the duodenum; and 25 and 17.5 for the ileum in the tammar and quokka, respectively. There was virtually no frequency gradient of the slow wave along the length of the small intestine in both macropods, which is extremely unusual. Action potentials were recorded from the quokka stomach but not from the tammar stomach. Action potentials were recorded from the small intestine of both species. The pattern of action potential activity was similar in both species. There were periods of up to 30 minutes during which the intestine was quiescent (q) with no action potential activity. This was followed by extended periods when bursts of action potentials occurred irregularly to be followed by periods of about 5 minutes when action potentials were associated with every slow wave.

scholarly journals Temporal coupling of field potentials and action potentials in the neocortex

2017 ◽  
Author(s):  
Brendon O. Watson ◽  
Mingxin Ding ◽  
György Buzsáki
Keyword(s):  
Action Potential ◽  
Action Potentials ◽  
Field Potential ◽  
Electromyographic Activity ◽  
Action Potential Firing ◽  
Firing Rates ◽  
Potential Firing ◽  
Temporal Coupling ◽  
Potential Activity ◽  
The Relationship

AbstractThe local field potential (LFP) is an aggregate measure of group neuronal activity and is often correlated with the action potentials of single neurons. In recent years investigators have found that action potential firing rates increase during elevations in power high-frequency band oscillations (50-200 Hz range). However action potentials also contribute to the LFP signal itself, making the spike–LFP relationship complex. Here we examine the relationship between spike rates and LFPs in varying frequency bands in rat neocortical recordings. We find that 50-180Hz oscillations correlate most consistently with high firing rates, but that other LFPs bands also carry information relating to spiking, including in some cases anti-correlations. Relatedly, we find that spiking itself and electromyographic activity contribute to LFP power in these bands. The relationship between spike rates and LFP power varies between brain states and between individual cells. Finally, we create an improved oscillation-based predictor of action potential activity by specifically utilizing information from across the entire recorded frequency spectrum of LFP. The findings illustrate both caveats and improvements to be taken into account in attempts to infer spiking activity from LFP.

scholarly journals The myogenic component in distention-induced peristalsis in the guinea pig small intestine

2001 ◽  
Vol 280 (3) ◽  
pp. G491-G500 ◽  
Author(s):  
Graeme Donnelly ◽  
Timothy D. Jackson ◽  
Krista Ambrous ◽  
Jing Ye ◽  
Adeel Safdar ◽  
...  
Keyword(s):  
Small Intestine ◽  
Guinea Pig ◽  
Slow Wave ◽  
Action Potentials ◽  
Slow Waves ◽  
Intraluminal Pressure ◽  
Control Activity ◽  
Potential Oscillations ◽  
Frequency Gradient

In an in vitro model for distention-induced peristalsis in the guinea pig small intestine, the electrical activity, intraluminal pressure, and outflow of contents were studied simultaneously to search for evidence of myogenic control activity. Intraluminal distention induced periods of nifedipine-sensitive slow wave activity with superimposed action potentials, alternating with periods of quiescence. Slow waves and associated high intraluminal pressure transients propagated aborally, causing outflow of content. In the proximal small intestine, a frequency gradient of distention-induced slow waves was observed, with a frequency of 19 cycles/min in the first 1 cm and 11 cycles/min 10 cm distally. Intracellular recording revealed that the guinea pig small intestinal musculature, in response to carbachol, generated slow waves with superimposed action potentials, both sensitive to nifedipine. These slow waves also exhibited a frequency gradient. In addition, distention and cholinergic stimulation induced high-frequency membrane potential oscillations (∼55 cycles/min) that were not associated with distention-induced peristalsis. Continuous distention produced excitation of the musculature, in part neurally mediated, that resulted in periodic occurrence of bursts of distally propagating nifedipine-sensitive slow waves with superimposed action potentials associated with propagating intraluminal pressure waves that caused pulsatile outflow of content at the slow wave frequency.

Effect of secretin on electrical activity of small intestine

1975 ◽  
Vol 229 (2) ◽  
pp. 484-488 ◽  
Author(s):  
AK Mukhopadhyay ◽  
LR Johnson ◽  
EM Copeland ◽  
NW Weisbrodt
Keyword(s):  
Small Intestine ◽  
Small Bowel ◽  
Electrical Activity ◽  
Slow Wave ◽  
Intravenous Infusion ◽  
Action Potentials ◽  
Slow Waves ◽  
Wave Frequency ◽  
Conscious Dogs ◽  
Total Percentage

The effect of intravenously administered secretin (0.5, 2.0, 6.0 U/kg-h) and intraduodenal acidification (13.2 meq/h HCl) on the electrical activity of the small bowel of three conscious dogs with gastric and duodenal cannulas was observed. Electrical activity was recorded in fasted as well as fed conditions through silver wire electrodes implanted along the entire length of the small bowel. Intravenous infusion of secretin in all dosages and in all dogs delayed the onset of the interdigestive myoelectric complex and reduced the total percentage of slow waves with superimposed spike potentials. Intraduodenal acidification also inhibited the interdigestive myoelectric complex, which developed incompletely with fewer action potentials on slow waves. Secretin did not produce any alteration in the fed pattern of activity, slow-wave frequency, or the caudal migration of the interdigestive myoelectric complex. The present study indicates that the nuerohumoral mechanisms responsible for initiation of the interdigestive myoelectric complex may be different from those responsible for its caudal migration.

scholarly journals Action-potential broadening and endogenously sustained bursting are substrates of command ability in a feeding neuron of Pleurobranchaea

1980 ◽  
Vol 43 (3) ◽  
pp. 669-685 ◽  
Author(s):  
R. Gillette ◽  
M. U. Gillette ◽  
W. J. Davis
Keyword(s):  
Action Potential ◽  
Action Potentials ◽  
Motor Output ◽  
Buccal Ganglion ◽  
Short Pulses ◽  
Motor Network ◽  
Single Axon ◽  
Network Output ◽  
Bilateral Pair ◽  
Potential Activity

1. The ventral white cells (VWC's) of the buccal ganglion of Pleurobranchaea, so named for their position and color, are a bilateral pair of neuron somata. Each sends a single axon out its contralateral stomatogastric nerve and has a dendritic field originating close to the soma. 2. The vwcs exhibit spontaneous episodes of prolonged depolarization (duration 1--4 min) accompanied by repetitive action-potential activity and separated by regular intervals of 3--30 min. Such prolonged burst episodes can be triggered by short pulses of depolarizing current. During the repetitive activity of the spontaneous bursts or that driven by imposed depolarization, the action potentials progressively broaden to 5--16 times their initial duration. 3. During spontaneous bursting or activity driven by imposed depolarization, the cyclic motor output of the feeding network is initiated or accelerated with a latency corresponding with the development of appreciable VWC spike broadening. When broadening of antidromic VWC spikes is suppressed by imposed hyperpolarization of the soma, the frequency of feeding cycles is significantly lower than when broadened spikes are allowed to develop. When trains of spikes are driven by depolarizing current, the motor output of the feeding network is not initiated until the VWC spikes have broadened to a repeatable "threshold" duration, regardless of the intensity of the depolarizing current. 4. The endogenous production of prolonged burst episodes, triggered by depolarizing current pulses, and progressive spike broadening can be demonstrated in the surgically isolated VWC soma. 5. The paired VWCs are strongly electrically coupled and display highly synchronous activity. They receive synaptic inputs from many previously identified interneurons of the feeding network and are thus reciprocally coupled within the network. 6. These results demonstrate that the capacity of this neuron to generate broadened action potentials during repetitive activity confers the ability to command coordinated motor-network output. The appropriate repetitive activity can be produced endogenously in the form of prolonged bursts of spikes.

Migrating spike complex in the small intestine of the fasting cat

1993 ◽  
Vol 265 (4) ◽  
pp. G619-G627
Author(s):  
W. C. De Vos
Keyword(s):  
Small Intestine ◽  
Action Potential ◽  
Electrical Activity ◽  
Slow Wave ◽  
Close Association ◽  
Slow Waves ◽  
Wave Frequency ◽  
Laboratory Animals ◽  
Variable Frequency ◽  
Implanted Electrodes

This study characterizes the migrating spike complex (MSC) in the small intestine of the awake fasting cat and compares the MSC with interdigestive activity in the small intestine of other species. Electrical activity in each of 12 cats with implanted electrodes showed MSCs, bands of spike potentials which attenuated slow-wave frequency and amplitude as the MSCs progressed distally. MSCs occurred at variable frequency with intervals ranging from < 1 min to > 5 h and averaged 51.2 +/- 2.8 (SE) min. MSCs migrated at 1-8 mm/s, accelerating distally; the duration decreased distally such that the length of the bowel in a burst (2-3 cm proximally) was conserved. The MSC was associated with an intense prolonged contraction of duration similar to that of the MSC. Sometimes the MSCs occurred in close association, and when an MSC period was < 5.7 min, the second MSC propagated at a slower rate than the first. Frequently, a brief series of slow wave-associated spikes preceded an MSC. MSCs were not associated with slow waves. The MSC differs in several respects from the migrating myoelectric complex of other laboratory animals and is more appropriately classified in a category that includes giant migrating spikes, prolonged propagated contractions, power contractions, and migrating action potential complexes.

Intestinal myoelectric alterations in rats chronically infected with the tapeworm Hymenolepis diminuta

1994 ◽  
Vol 267 (5) ◽  
pp. G851-G858 ◽  
Author(s):  
M. B. Dwinell ◽  
P. Bass ◽  
J. A. Oaks
Keyword(s):  
Small Intestine ◽  
Potential Gradient ◽  
Hymenolepis Diminuta ◽  
Phase Iii ◽  
Myoelectric Activity ◽  
Spike Potential ◽  
Bipolar Electrodes ◽  
Distal Small Intestine ◽  
Potential Activity ◽  
Interdigestive Motility

This study determined that intestinal myoelectric activity was profoundly altered during a strictly luminal, chronic, tapeworm infection. Chronically implanted bipolar electrodes were attached to five sites on the serosal surface of the rat small intestine. One was placed on the duodenum, three on the jejunum, and the fifth on the ileum. Electromyographic recording in nonfasted unanesthetized animals was begun at day 5 postsurgery. All electromyographic recordings were analyzed for slow wave (SW) frequency, phase III frequency, duration of phase III, and percentage of SW with spike potentials. Three initial control recordings prior to infection confirmed the presence of normal interdigestive motility characterized by the three phases (I, II, III) of the migrating myoelectric complex (MMC). Two nonpropulsive myoelectric alterations were observed in infected animals: the repetitive bursts of action potentials (RBAP) and periods of sustained spike potentials (SSP). Myoelectric activity from infected animals indicated decreased cycling of the interdigestive MMC. RBAP and SSP were more prevalent in the distal small intestine corresponding to tapeworm location. The percent of spike potential activity indicated that there was a reversal in the spike potential gradient on the small intestine. The number of spike potentials was maximal in caudal and minimal in oral intestine. We propose that overall localized increases in myoelectric spike potential activity represent increased contractility and decreased propulsion triggered by the presence of the tapeworm. These motility changes were surprising, since the tapeworm Hymenolepis diminuta does not penetrate the intestinal mucosa. This interaction between parasite and host may prevent expulsion of the tapeworm from the small intestine.

scholarly journals Optical mapping of cryoinjured rat myocardium grafted with mesenchymal stem cells

2012 ◽  
Vol 302 (1) ◽  
pp. H270-H277 ◽  
Author(s):  
Andrea R. Costa ◽  
Nikhil C. Panda ◽  
Sandro Yong ◽  
Maritza E. Mayorga ◽  
Gary P. Pawlowski ◽  
...  
Keyword(s):  
Stem Cells ◽  
Mesenchymal Stem Cells ◽  
Action Potential ◽  
Action Potentials ◽  
Connexin 43 ◽  
Optical Mapping ◽  
Left Ventricular ◽  
Viable Myocardium ◽  
Simultaneous Action ◽  
Potential Activity

Mesenchymal stem cells (MSCs) have been shown to improve cardiac electrophysiology when administered in the setting of acute myocardial infarction. However, the electrophysiological phenotype of MSCs in situ is not clear. We hypothesize that MSCs delivered intramyocardially to cryoinjured myocardium can engraft, but will not actively generate, action potentials. Cryoinjury-induced scar was created on the left ventricular epicardial surface of adult rat hearts. Within 30 min, hearts were injected with saline (sham, n = 11) or bone marrow-derived MSCs (2 × 106) labeled with 1,1′-dioctadecyl-3,3,3,3′-tetramethylindocarbocyanine percholate (DiI; n = 16). At 3 wk, optical mapping and cell isolation were used to measure optical action potentials and calcium transients, respectively. Histological analysis confirmed subepicardial scar thickness and the presence of DiI-positive cells that express connexin-43. Optical action potential amplitude within the scar at MSC-positive sites (53.8 ± 14.3%) was larger compared with sites devoid of MSCs (35.3 ± 14.2%, P < 0.05) and sites within the scar of shams (33.5 ± 6.9%, P < 0.05). Evidence of simultaneous action potential upstroke, the loss of action potential activity following ablation of adjacent viable myocardium, and no rapid calcium transient response in isolated DiI+ cells suggest that the electrophysiological influence of engrafted MSCs is electrotonic. MSCs can engraft when directly injected into a cryoinjury and are associated with evidence of action potential activity. However, our results suggest that this activity is not due to generation of action potentials, but rather passive influence coupled from neighboring viable myocardium.

Slow wave and spike action potentials recorded in cell cultures from the muscularis externa of the guinea pig small intestine

1999 ◽  
Vol 77 (8) ◽  
pp. 598-605 ◽  
Author(s):  
Rosa Espinosa-Luna ◽  
Stephen M Collins ◽  
Luis M Montaño ◽  
Carlos Barajas-López
Keyword(s):  
Small Intestine ◽  
Guinea Pig ◽  
Cell Cultures ◽  
Slow Wave ◽  
Action Potentials ◽  
Critical Mass ◽  
Slow Waves ◽  
Intracellular Recordings ◽  
Spontaneous Movements ◽  
Muscularis Externa

Intracellular recordings were obtained to investigate whether slow wave and spike type action potentials are present in cell cultures of the muscularis externa from the guinea pig small intestine. The muscularis externa of the small intestine was dissociated by using specific purified enzymes and gentle mechanical dissociation. Cells were plated on cover slips and maintained in culture for up to 4 weeks. Dissociated cells obtained in this way reorganized themselves in a few days to form small cell clumps showing spontaneous movements. Intracellular recordings of these clumps displayed both spike and slow wave type action potentials. Spikes were observed on top of some slow waves and were abolished by the addition of nifedipine or the removal of extracellular calcium. Slow waves, however, were nifedipine insensitive and temperature sensitive, and were abolished by octanol (a gap junction blocker) and forskolin (an adenyl cyclase activator). Slow waves were never observed in small clumps (<50 µm), suggesting that a critical mass of cells might be required for their generation. These observations demonstrated for the first time the presence of nifedipine-insensitive slow waves in cell cultures of the muscularis externa from the guinea pig small intestine. Cell cultures allow rigorous control of the immediate environment for the cells and this should facilitate future studies on the molecular and cellular mechanisms responsible for the slow waves in the gastrointestinal tract.Key words: smooth muscle, slow waves, spiking activity, gastrointestinal tract, gut, small intestine, electrophysiology, pacemaker activity, guinea pig.

Components of the cardiac action potential

1962 ◽  
Vol 203 (2) ◽  
pp. 258-260 ◽  
Author(s):  
T. Hoshiko ◽  
Nick Sperelakis
Keyword(s):  
Action Potential ◽  
Slow Wave ◽  
Action Potentials ◽  
The Other ◽  
Cardiac Action Potential ◽  
Intercalated Disc ◽  
Ringer’S Solution ◽  
Current Pulses ◽  
Cardiac Action ◽  
Intracellular Action

Two components have been observed in the intracellular action potentials of frog ventricular strips under conditions of impaired transmission. The strips were bathed in Ca-free, Mg Ringer's solution and were subjected to passage of current pulses through their length. Under these conditions a "notch" gradually developed at the beginning of the plateau and separated the action potential into a spike and a slow wave. In any given cell, the notch was often more prominent when the conditioned strip was stimulated from one end than from the other. Occasionally a spike in isolation spontaneously alternated with a spike plus slow wave response. The slow waves were generally graded in duration and magnitude with stimulus intensity or duration. The results are discussed in terms of a possible junctional response at the intercalated disc.

Alteration of myoelectric activity of small intestine by invasive Escherichia coli

1980 ◽  
Vol 238 (1) ◽  
pp. G57-G62
Author(s):  
T. W. Burns ◽  
J. R. Mathias ◽  
J. L. Martin ◽  
G. M. Carlson ◽  
R. P. Shields
Keyword(s):  
Escherichia Coli ◽  
Small Intestine ◽  
Action Potential ◽  
Action Potentials ◽  
Myoelectric Activity ◽  
Ileal Loop ◽  
Discharge Activity ◽  
Electrode Recording ◽  
Proximal Small Intestine ◽  
Potential Complex

Invasive strains of Escherichia coli (4608-58 and TD 213 CL) altered myoelectric activity of the small intestine in New Zealand White rabbits. The altered myoelectric activity had two distinct complex patterns. The first was defined as repetitive bursts of action potentials (RBAPs) that occurred predominantly in infected ligated ileal loops. The RBAP activity is characterized by action potential discharge activity greater than 1.5 s in duration and occurring on three or more successive slow waves on the same electrode recording site. These bursts of action potentials often migrated to adjacent electrode sites. The second complex pattern, defined as the migrating action potential complex (MAPC), occurred predominantly in the uninfected small intestine orad to the ligated ileal loop. The MAPC consists of action potential discharge activity of 2.5 s or longer that propagates aborally over at least two consecutive electrode sites. These studies demonstrated an altered myoelectric pattern, the RBAP, characteristic of invasion within the infected ligated loop. The MAPC, characteristic of noninvasion, was noted in the uninfected proximal small intestine.

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