The specific long spike burst pattern indicates the presence of regional variability in the ovine gallbladder motor function

AbstractThe myoelectrical activity of ovine gallbladder is incompletely recognized. Accordingly, each of five rams was fitted with six small intestinal and three gallbladder electrodes. The strain gauge force transducer was also mounted near the gallbladder fundic electrode. In two series of chronic experiments the electromyographical and mechanical recordings were conducted during 5–7 h in fasted or non-fasted animals, with or without feeding. The occurrence of the slow waves in the small bowel was common, unlike those in the gallbladder. In the small bowel myoelectrical records both the migrating motility complex and minute rhythm pattern were observed regularly. In the gallbladder, both the migrating motility complex-like activity and the minute rhythm were also denoted in the same time as in the small bowel. In gallbladder infundibulum, and often also in the gallbladder corpus, the specific pattern, called the long spike burst pattern (LSBP) was observed. It comprised usually one or two parts of prolonged duration. The first part resembled the classical (short lasting) spike burst in the small bowel and its amplitude was lower than that of the second part. The spike burst frequency of the second part of the pattern was 2–3 times lower than that of the first part. During phase 1 – and phase 2a-like activity, the frequency of the gallbladder LSBP was reduced in fasted rams. The LSBP amplitude was relatively high and not further enhanced after feeding. In fasted rams, the duration of specific pattern, observed in gallbladder infundibulum, was longer than that in non-fasted animals and its amplitude was low. Similar events were recorded in the gallbladder corpus, but the LSBP was shorter and not regular. In the gallbladder fundus, mostly irregular short spike bursts were recorded. It is concluded that in sheep, specific types of the long-lasting groups of spikes occur in the upper gallbladder areas forming the specific pattern that indicates the presence of the regional variability of the gallbladder motor activity. The character of LSBP depends mostly on feeding conditions.

Download Full-text

Occurrence of the specific long spike burst pattern in the ovine proximal gallbladder as an indication of myoelectric regional variability

Onderstepoort Journal of Veterinary Research ◽

10.4102/ojvr.v85i1.1455 ◽

2018 ◽

Vol 85 (1) ◽

Author(s):

Krzysztof W. Romański ◽

Józef Nicpoń

Keyword(s):

Regional Variability ◽

Spike Burst ◽

Burst Pattern

Download Full-text

Changes in jejunal myoelectrical activity during exercise in fed untrained dogs

AJP Gastrointestinal and Liver Physiology ◽

10.1152/ajpgi.1988.254.5.g741 ◽

1988 ◽

Vol 254 (5) ◽

pp. G741-G747

Author(s):

M. J. Kenney ◽

A. Flatt ◽

R. W. Summers ◽

C. K. Brown ◽

C. V. Gisolfi

Keyword(s):

Gastrointestinal Symptoms ◽

Proximal Jejunum ◽

Regular Spike ◽

Short Term ◽

Burst Frequency ◽

Myoelectrical Activity ◽

Spike Burst ◽

Bipolar Electrodes ◽

Exercise Induced ◽

Spike Bursts

Seven female dogs (15-20 kg) were instrumented with seven bipolar electrodes sutured at 3-cm intervals to the serosal surface of the proximal jejunum and were exercised at different intensities and durations on a motor-driven treadmill. Slow-wave frequency increased (P less than 0.05) from preexercise control during prolonged (90 min) exercise and during recovery after short-term exercise (30 min) at 70% heart rate reserve (HRR). These changes were associated with an increase in core temperature. Spike-burst frequency (SBF) increased (P less than 0.05) with moderate exercise (50% HRR), but the magnitude was small. When exercise was extended beyond 30 min and during all recovery periods, SBF decreased significantly. Exercise produced migrating myoelectrical complexes in three experiments and less dramatic pattern changes characterized as "clustered contractions" (regular spike bursts preceded and followed by the absence of spike bursts) in at least nine other experiments. We conclude that exercise does alter jejunal myoelectrical activity, but myoelectrical patterns may be more important in explaining exercise-induced gastrointestinal symptoms than changes in spike-burst frequency or duration.

Download Full-text

The spinal GABA system modulates burst frequency and intersegmental coordination in the lamprey: differential effects of GABAA and GABAB receptors

Journal of Neurophysiology ◽

10.1152/jn.1993.69.3.647 ◽

1993 ◽

Vol 69 (3) ◽

pp. 647-657 ◽

Cited By ~ 64

Author(s):

J. Tegner ◽

T. Matsushima ◽

A. el Manira ◽

S. Grillner

Keyword(s):

Spinal Cord ◽

Locomotor Activity ◽

Gabaa Receptor ◽

Gabab Receptor ◽

Gaba Uptake ◽

Phase Lag ◽

Fictive Locomotion ◽

Burst Frequency ◽

Intersegmental Coordination ◽

Burst Pattern

1. The effect of spinal GABAergic neurons on the segmental neuronal network generating locomotion has been analyzed in the lamprey spinal cord in vitro. It is shown that gamma-aminobutyric acid (GABA)A- and GABAB-mediated effects influence the burst frequency and the intersegmental coordination and that the GABA system is active during normal locomotor activity. 2. Fictive locomotor activity was induced by superfusing the spinal cord with a Ringer solution containing N-methyl-D-aspartate (NMDA, 150 microM). The efferent locomotor activity was recorded by suction electrodes from the ventral roots or intracellularly from interneurons or motoneurons. If a GABA uptake blocker was added to the perfusate, the burst rate decreased. This effect was counteracted by GABAB receptor blockade by phaclofen or 2-(OH)-saclofen. If instead a GABAB receptor agonist (baclofen) was added during fictive locomotion, a depression of the burst rate occurred. It was concluded that a GABAB receptor activation due to an endogenous release of GABA caused a depression of the burst activity with a maintained well-coordinated locomotor activity. 3. If a GABAA receptor antagonist (bicuculline) is applied during fictive locomotion elicited by NMDA, a certain increase of the burst rate occurred. Conversely, if a selective GABAA agonist (muscimol) was administered, the burst rate decreased. Similarly, if the GABAA receptor activity was potentiated by activation of a benzodiazepine site by diazepam, the burst rate was reduced. If, however the GABAergic effect was first enhanced by an uptake blocker (nipecotic acid), an administration of a GABAA antagonist (bicuculline) increased the burst rate, but in addition, the burst pattern became less regular with recurrent shorter periods without clear reciprocal burst activity. The GABAA receptor activity appears important for the rate control and for permitting a regular burst pattern. 4. The intersegmental coordination in the lamprey is characterized by a rostrocaudal constant phase lag of approximately 1% of the cycle duration between the activation of consecutive segments during forward swimming. This rostrocaudal phase lag can be reversed during backward swimming, which can be induced also experimentally in the isolated spinal cord by providing a higher excitability to the caudal segments. In a split-bath configuration, a GABA uptake blocker or a GABAB agonist was administered to the rostral part of the spinal cord, which caused a reversal of the phase lag as during backward swimming. If GABAA receptors were blocked under similar conditions, the intersegmental coordination became irregular. It is concluded that an increased GABA activity in a spinal cord region can modify the intersegmental coordination.(ABSTRACT TRUNCATED AT 400 WORDS)

Download Full-text

Alteration in uterine contractility in mares with experimentally induced placentitis

Reproduction ◽

10.1530/rep.1.00021 ◽

2004 ◽

Vol 127 (1) ◽

pp. 57-66 ◽

Cited By ~ 24

Author(s):

J A McGlothlin ◽

G D Lester ◽

P J Hansen ◽

M Thomas ◽

L Pablo ◽

...

Keyword(s):

Activity Index ◽

Early Morning ◽

Late Gestation ◽

Uterine Contractility ◽

Myoelectrical Activity ◽

Spike Burst ◽

Streptococcus Equi ◽

Large Spike ◽

Small Spike ◽

Experimentally Induced

An experimental model of ascending placentitis was developed in the mare to characterize the uterine myoelectrical pattern in late gestation and determine how ascending placentitis altered this pattern. In experiment 1, myometrial electrical activity was analyzed during the early morning, late morning and evening hours in four mares in the last 15 days of gestation to identify patterns of activity. In experiment 2, nine mares received intra-cervical inoculations ofStreptococcus equisubspecieszooepidemicus. Myoelectrical activity in the early morning and evening hours in these mares was compared with four control mares. In experiment 1, the number of spike burst clusters >30 s was greater in the evening than in the late morning hours (P< 0.04). Spike burst activity (number × duration) of mares in experiment 1 was similar during day and night recordings until the last 6 days of gestation when it gradually increased each evening until parturition (P< 0.05). In experiment 2, control mares experienced a gradual increase in the number of small spike burst clusters in the last 6 days (P= 0.008) and an increase in large and small spike burst clusters in the evening hours in the last 4 days of gestation (P= 0.03). Mares with experimentally induced placentitis never exhibited a rise in spike burst clusters but had an increase in the mean duration and activity index of large spike burst clusters in the 4 days before parturition (P< 0.04). In conclusion, control mares had a progressive, reversible rise in myoelectrical activity at night in the week preceding parturition. This was not observed in mares with experimentally induced placentitis. They exhibited an increase in the intensity and duration of large spike burst clusters possibly in response to local inflammation.

Download Full-text

Effect of somatostatin on myoelectrical activity of small bowel.

AJP Endocrinology and Metabolism ◽

10.1152/ajpendo.1978.235.3.e249 ◽

1978 ◽

Vol 235 (3) ◽

pp. E249 ◽

Cited By ~ 4

Author(s):

P Thor ◽

R Król ◽

S J Konturek ◽

D H Coy ◽

A V Schally

Keyword(s):

Small Bowel ◽

Spike Activity ◽

Digestive System ◽

Hormone Release ◽

Myoelectrical Activity ◽

Meat Meal ◽

Type Pattern ◽

Dose Dependent Decrease ◽

Dose Dependent ◽

Higher Doses

Somatostatin, a growth hormone-release inhibiting hormone, has been found to be a powerful inhibitor of gastric and pancreatic secretion as well as of hormone release in the digestive system. This study was undertaken to determine the influence of somatostatin on the myoelectrical activity pattern of the small bowel. Three conscious dogs were prepared with electrodes spaced 25 cm apart along the entire small intestine. Intravenous infusions of somatostatin were administered in various doses (0.6--5.0 microgram/kg.h) while spike activity and slow waves were recorded under fasting conditions, after a meat meal, or during intravenous infusion of gastrin, caerulein, or insulin. Somatostatin at a dose of 0.6 microgram/kg.h almost doubled the frequency of the interdigestive myoelectric complex. Somatostatin in fed dogs caused a dose-dependent decrease of the normal fed spike activity, and at higher doses it induced a pattern like that seen in fasting animals. The slow-wave frequency in both fasted and fed conditions was not changed significantly. We conclude that somatostatin given under basal conditions increases the frequency of the interdigestive complex and, when administered after feeding, converts the fed-type pattern to the fasted-type pattern. It may therefore play a promoting role in initiating the interdigestive myoelectric complex.

Download Full-text

A model of myoelectrical activity recording after small bowel transplantation

Transplantation Proceedings ◽

10.1016/s0041-1345(98)00749-0 ◽

1998 ◽

Vol 30 (6) ◽

pp. 2611-2612

Author(s):

A.M. Minioli ◽

F.P. Lopasso ◽

E.R.S. Forno ◽

L.L.S. Larangeira ◽

S. Goldenberg ◽

...

Keyword(s):

Small Bowel ◽

Small Bowel Transplantation ◽

Myoelectrical Activity

Download Full-text

Influence of methionine-enkephalin and morphine on the myoelectrical activity of the small bowel

Gastroenterology ◽

10.1016/0016-5085(78)93581-3 ◽

1978 ◽

Vol 74 (5) ◽

pp. 1148

Author(s):

P.J. Thor ◽

R. Król ◽

R. Siebers ◽

S.J. Konturek ◽

D.H. Coy ◽

...

Keyword(s):

Small Bowel ◽

Myoelectrical Activity ◽

Methionine Enkephalin

Download Full-text

Effects of respiratory afferent stimulation on phrenic neurogram during hypoxic gasping in the cat

Journal of Applied Physiology ◽

10.1152/jappl.1993.75.5.2091 ◽

1993 ◽

Vol 75 (5) ◽

pp. 2091-2098 ◽

Cited By ~ 8

Author(s):

J. E. Melton ◽

L. O. Chae ◽

N. H. Edelman

Keyword(s):

Pattern Formation ◽

Carotid Sinus ◽

Superior Laryngeal Nerve ◽

Laryngeal Nerve ◽

Carotid Sinus Nerve ◽

Burst Frequency ◽

Burst Pattern ◽

Progressive Hypoxia ◽

Stimulation Period ◽

Stimulation Of

Previous studies suggested that phrenic motor output is largely refractory to afferent stimuli during gasping. We tested this concept by electrically stimulating the carotid sinus nerve (CSN) or the superior laryngeal nerve (SLN) of anesthetized peripherally chemodenervated vagotomized ventilated cats during eupnea or gasping induced by hypoxia. During eupnea, phrenic neurogram amplitude (PNA) increased by 110% during 30 s of supramaximal CSN stimulation, but burst frequency did not change. Progressive hypoxia caused gasping after arterial O2 content was reduced by 75%. During gasping, CSN stimulation caused premature onset of gasp in 12 of 13 trials, shortened intergasp interval [6.3 +/- 0.9 vs. 14.8 +/- 2.5 (SE) s], and resulted in a small (20%) but significant increase in PNA. Intensity of SLN stimulation was adjusted to abolish phrenic activity during the 30-s eupneic stimulation period. During gasping, SLN stimulation of the same intensity tended to delay onset of the next gasp, increased intergasp interval (16.9 +/- 1.9 vs. 13.3 +/- 1.2 s), and reduced PNA by 32%. Thus the respiratory burst pattern formation circuitry responds to afferent stimuli during gasping, albeit in a manner different from the eupneic response. These observations suggest that gasping is the output of a modified eupneic burst pattern formation circuit.

Download Full-text