Initiation of migrating myoelectric complexes in human subjects: role of duodenal acidification and plasma motilin

1981 ◽  
Vol 59 (2) ◽  
pp. 173-179 ◽  
Author(s):  
E. E. Daniel ◽  
J. E. T. Fox ◽  
S. M. Collins ◽  
T. D. Lewis ◽  
M. Meghji ◽  
...  
Keyword(s):  
Human Subjects ◽  
Duodenal Bulb ◽  
Maximal Activity ◽  
Phase Iii ◽  
Motor Complex ◽  
Duodenal Acidification ◽  
Normal Human ◽  
Plasma Motilin ◽  
The Relationship

The hypothesis that acid, emptied intermittently from the stomach during fasting, might initiate the duodenal phase of the migrating motor complex was tested in normal human subjects, in addition, the relationship between plasma motilin concentrations and the initiation of migrating motor complexes was examined. Migrating complexes occurred spontaneously in the absence of acid in the duodenal bulb and in the presence of duodenal bulb neutralization with sodium bicarbonate. Thus duodenal bulb acidification is not necessary for initiation of the duodenal phase of the migrating motor complexes. Further-more, cyclical increases in plasma motilin concentrations were not closely correlated with the initiation of the gastric phase of maximal activity of the migrating motor complexes. However, motilin concentrations were decreased significantly following onset of the duodenal phase III. We conclude that neither duodenal acidification nor increases in motilin concentration are necessary to initiate migrating motor complexes in man.

Relationship of plasma motilin concentration to fat ingestion, duodenal acidification and alkalinization, and migrating motor complexes in dogs

1981 ◽  
Vol 59 (2) ◽  
pp. 180-187 ◽  
Author(s):  
J. E. T. Fox ◽  
N. S. Track ◽  
E. E. Daniel
Keyword(s):  
Species Difference ◽  
Maximal Activity ◽  
Significant Rise ◽  
Migrating Motor Complex ◽  
Phase Iii ◽  
Complex Activity ◽  
Duodenal Motility ◽  
Motor Complex ◽  
Duodenal Acidification ◽  
Plasma Motilin

Plasma motilin concentrations were measured in dogs following duodenal acidification and alkalinization and gastric instillation of fat. Antral and duodenal motility were recorded concurrently using intraluminal manometry. Alkalinization of the duodenum produced an increase in antral and duodenal motility and a significant rise in plasma motilin. Alkaline infusions at 5 mL/min into the duodenum initiated phase III of a migrating motor complex both in the antrum and in the duodenum. Duodenal acid infusions produced no change in plasma motilin concentrations while inhibiting antral motility and stimulating duodenal motility for the duration of the infusion. Gastric instillation of 60 g fat produced a 25% increase above basal motilin levels at 50 min after instillation. Motilin levels monitored during spontaneous migrating motor complexes showed peak motilin levels occurring during maximal activity of the antral duodenal region in seven out of nine motor complexes examined but motilin peaks also occurred without migrating complexes being present in this area and, as well, complexes occurred when motilin was undetectable. These results taken together with our other studies in man confirm that a true species difference exists between man and dog in the hormonal motor response to duodenal alkalinization. Although a relationship appears to exist between the appearance of maximal migrating motor complex activity in the gastroduodenal area and plasma motilin concentrations in dogs as in humans, the motilin peaks are probably neither necessary nor sufficient to induce phase III activity.

Increase of swallows before onset of phase III of migrating motor complex in normal human subjects

1996 ◽  
Vol 41 (3) ◽  
pp. 522-527 ◽  
Author(s):  
Leonardo Marzio ◽  
Laurino Grossi ◽  
Mariassunta Falcucci ◽  
Antonio Francesco Ciccaglione ◽  
Maria Grazia Malatesta ◽  
...  
Keyword(s):  
Human Subjects ◽  
Migrating Motor Complex ◽  
Phase Iii ◽  
Motor Complex ◽  
Normal Human

Motor cycles with phase III in antrum are associated with high motilin levels and prolonged gallbladder emptying

1993 ◽  
Vol 264 (4) ◽  
pp. G596-G600 ◽  
Author(s):  
M. F. Stolk ◽  
K. J. van Erpecum ◽  
A. J. Smout ◽  
L. M. Akkermans ◽  
J. B. Jansen ◽  
...  
Keyword(s):  
Bile Acid ◽  
Cycle Length ◽  
Phase Iii ◽  
Gallbladder Motility ◽  
Gallbladder Emptying ◽  
Motor Complex ◽  
Group 2 ◽  
Relationship Of ◽  
The Relationship ◽  
Group 1

We examined the relationship of interdigestive gallbladder emptying with the different phases of the migrating motor complex (MMC) and with plasma levels of cholecystokinin (CCK) and motilin. In 10 volunteers 20 cycles of the MMC were recorded. In 11 cycles phase III occurred in antrum and duodenum (group 1). In nine cycles phase III was observed only in duodenum (group 2). In group 1 gallbladder emptying started at 30% of total cycle length and continued until the end of the cycle. Maximal gallbladder emptying was 33.3 +/- 3.3% (SE). In group 2 gallbladder emptying also started at 30% of total cycle length but ended at 60%. Maximal gallbladder emptying in this group was 24.3 +/- 3.1% (P < 0.05). Motilin levels were higher in group 1 than in group 2 during phase IIB (240.1 +/- 28.5 and 142.1 +/- 30.9 pg/ml, respectively, P < 0.05) and during phase III (210.8 +/- 24.3 and 93.5 +/- 12.5 pg/ml, respectively, P < 0.05). We conclude that: 1) phase III activities starting in the antrum are preceded by greater and prolonged gallbladder emptying, higher motilin levels, and higher intraduodenal bile acid concentrations than phase III activities starting in the duodenum and 2) no relationship between interdigestive gallbladder motility and CCK levels could be demonstrated.

Fasting and postprandial hepatic bile flow in unanesthetized opossums

1990 ◽  
Vol 259 (5) ◽  
pp. G745-G752 ◽  
Author(s):  
I. Takahashi ◽  
M. K. Kern ◽  
W. J. Dodds ◽  
W. J. Hogan ◽  
R. D. Layman ◽  
...  
Keyword(s):  
Bile Acid ◽  
Bile Flow ◽  
Common Duct ◽  
Enterohepatic Circulation ◽  
Phase Iii ◽  
Hepatic Bile ◽  
Bipolar Electrodes ◽  
Motor Complex ◽  
The Common ◽  
The Relationship

In conscious opossums, we evaluated the relationship between hepatic bile flow and the intestinal motor function during fasting as well as after feeding. In six opossums, bipolar electrodes were implanted from the gastric antrum to the terminal ileum. After cholecystectomy, the common duct was ligated, and a catheter was tied into the proximal common duct for collecting hepatic bile. During subsequent studies, hepatic bile flow was measured, and bile was returned to the duodenum through an externalized duodenal catheter. Cyclic increases in bile flow during fasting did not show a close correlate with the duodenal migratory motor complex (MMC) cycle. Rather, bile flow showed peak values [0.11 +/- 0.02 (SE) ml/min] when phase III MMC activity reached the midileum. Hepatic bile flow correlated closely with the amount of bile acid secreted by the liver. When the bile acid pool was depleted by diverting bile from the intestine, hepatic secretion of bile fell to uniformly low values of approximately 0.04 ml/min that did not show cyclic variation. Hepatic bile flow after feeding increased to a maximal value of 0.12 +/- 0.01 ml/min at 90 min. We conclude that increases in hepatic bile flow during fasting and after meals are determined mainly by variations in intestinal motor activity that alter small bowel transit and thereby affect the enterohepatic circulation of bile acids.

Role of Change in Vitamin D Metabolism with Age in Calcium and Phosphorus Metabolism in Normal Human Subjects*

1984 ◽  
Vol 59 (4) ◽  
pp. 719-726 ◽  
Author(s):  
YOSHIKI FUJISAWA ◽  
KAICHI KIDA ◽  
HIROSHI MATSUDA
Keyword(s):  
Vitamin D ◽  
Human Subjects ◽  
Phosphorus Metabolism ◽  
Vitamin D Metabolism ◽  
Normal Human ◽  
Calcium And Phosphorus

Voluntary activation of human quadriceps during and after isokinetic exercise

1991 ◽  
Vol 71 (6) ◽  
pp. 2122-2126 ◽  
Author(s):  
D. J. Newham ◽  
T. McCarthy ◽  
J. Turner
Keyword(s):  
Human Subjects ◽  
Knee Extension ◽  
Voluntary Activation ◽  
Isometric Contractions ◽  
Knee Angle ◽  
Lower Velocity ◽  
Isokinetic Contractions ◽  
Normal Human ◽  
Voluntary Contractions ◽  
The Relationship

The extent of voluntary activation in fresh and fatigued quadriceps muscles was investigated during isometric and isokinetic voluntary contractions at 20 and 150 degrees/s in 23 normal human subjects. The muscles were fatigued by a total of 4 min of maximal knee extension at an angular velocity of 85 degrees/s. Voluntary activation was determined by the superimposition of tetanic electrical stimulation at 100 Hz for 250 ms, initiated at a constant knee angle. The relationship between voluntary and stimulated force was similar to that found with the established twitch superimposition technique used on isometric contractions. In fresh muscle all the subjects showed full voluntary activation during isometric contractions. Some activation failure was seen in five subjects at 20 degrees/s [2.0 +/- 0.9 degrees (SE)] and in two subjects at 150 degrees/s (0.7 +/- 0.5). After fatigue all subjects showed some activation failure at 0 and 20 degrees/s (36.4 +/- 3.1 and 28.8 +/- 4.1 degrees, respectively), but only two showed any at 150 degrees/s (1.4 +/- 5.7). We conclude that brief high-intensity dynamic exercise can cause a considerable failure of voluntary activation. This failure was most marked during isometric and the lower-velocity isokinetic contractions. Thus a failure of voluntary activation may have greater functional significance than previous studies of isometric contractions have indicated.

Interdigestive intestinal motility in dogs with chronic exclusion of bile from the digestive tract

1987 ◽  
Vol 65 (12) ◽  
pp. 2493-2496 ◽  
Author(s):  
Victor Plourde ◽  
Louise Trudel ◽  
Pierre Poitras
Keyword(s):  
Health Status ◽  
Bile Duct ◽  
Urinary Bladder ◽  
Motor Activity ◽  
Digestive Tract ◽  
Foley Catheter ◽  
Phase Iii ◽  
Excellent Health ◽  
Plasma Motilin

To elucidate the role of bile delivery into the duodenum on the regulation of plasma motilin and on the interdigestive migrating complex, three dogs were operated upon to ligate the main bile duct and divert the biliary flow into the urinary bladder via a Foley catheter. After the operation, despite the chronic diversion of bile from the digestive tract, all animals maintained an excellent health status and exhibited recurrent periods of phase III motor activity migrating from the duodenum to the ileum, which were associated with cyclic increases in plasma motilin. Following the infusion of pooled dog bile (1 mL/min for 10 min) into the duodenum, a premature phase III and a concomitant rise in plasma motilin were observed. These results suggest, that although bile delivery into the duodenum can induce motilin increase in plasma and period of phase III activity in the gut, this phenomenon does not constitute an essential stimulus for the release of motilin and for the induction of the phase III of the interdigestive migrating complex.

scholarly journals Effects of the Hormone Kisspeptin on Reproductive Hormone Release in Humans

2014 ◽  
Vol 2014 ◽  
pp. 1-10 ◽  
Author(s):  
Joanne L. Calley ◽  
Waljit S. Dhillo
Keyword(s):  
Human Subjects ◽  
Reproductive Function ◽  
Current Data ◽  
Loss Of Function ◽  
Potential Therapeutic Role ◽  
Human Reproductive ◽  
Normal Human ◽  
Gonadotrophin Releasing Hormone ◽  
Research Avenue

The kisspeptins are a family of neuropeptides which act as upstream stimulators of gonadotrophin releasing hormone (GnRH) neurons. Kisspeptin signalling is prerequisite to establishing the normal human reproductive phenotype; loss of function mutations in the KISS1 or KISS1R gene produces normosmic hypogonadotrophic hypogonadism in humans and mice, whilst increased activation of KISS1R causes precocious puberty. Administration of exogenous kisspeptin to human subjects stimulates an acute gonadotrophin rise. Serum kisspeptin levels also markedly increase during pregnancy. The identification of kisspeptin has been one of the biggest discoveries in the field of reproductive endocrinology, since the isolation and sequencing of GnRH in 1977, and has generated a novel research avenue which has received much attention over the past decade. This research has delineated many properties of the KISS1-KISS1R system, but there is still further work to do. Understanding kisspeptin’s role throughout our reproductive lifetime should help us better understand—and therefore treat—disorders of reproductive function. Promisingly, the current data supports the potential to develop kisspeptin based therapies. As an outlook article this paper focusses predominantly on our groups recent investigations into the effects of kisspeptin administration to humans and the potential therapeutic role of kisspeptin.

Endogenous ghrelin and 5-HT regulate interdigestive gastrointestinal contractions in conscious rats

2008 ◽  
Vol 295 (2) ◽  
pp. G403-G411 ◽  
Author(s):  
Hiroshi Taniguchi ◽  
Hajime Ariga ◽  
Jun Zheng ◽  
Kirk Ludwig ◽  
Christopher Mantyh ◽  
...  
Keyword(s):  
Duodenal Mucosa ◽  
Phase Iii ◽  
Duodenal Juice ◽  
Ghrelin Receptor ◽  
Conscious Rats ◽  
Freely Moving ◽  
The Relationship ◽  
Distal Jejunum ◽  
Spontaneous Phase

Endogenous ghrelin causes interdigestive contractions of the stomach in rats. In contrast, previous studies showed that 5-HT3 and 5-HT4 receptors were involved in regulating intestinal interdigestive contractions. We studied the possible role of endogenous ghrelin and 5-HT regulating interdigestive gastrointestinal (GI) contractions in rats. Four strain gauge transducers were implanted on the antrum, duodenum, and proximal and distal jejunum. After an overnight fast, GI contractions were recorded in freely moving conscious rats and ghrelin receptor antagonists [(d-lys3)GHRP6; 1 μmol/kg], 5-HT3 antagonists (Ondansetron; 0.5 mg/kg) and 5-HT4 antagonists (GR 125,487; 1 mg/kg) were administered (bolus iv). To evaluate the relationship between the luminal concentrations of 5-HT and phase III-like contractions of the duodenum, duodenal juice was collected via the intraduodenal catheter. 5-HT content of the duodenal juice was measured by HPLC. (d-lys3)GHRP6 significantly attenuated the occurrence and amplitude of phase III-like contractions of the antrum, but not the duodenum and jejunum. 5-HT4 antagonists significantly reduced spontaneous phase III-like contractions of the jejunum, without affecting those of the antrum and duodenum. In contrast, 5-HT3 antagonists did not affect phase III-like contractions in GI tract. Luminal concentration of 5-HT at the phase III-like contraction (36.0 ± 13.3 ng/ml, n = 9) was significantly higher than that at the phase I-like contractions of the duodenum (4.9 ± 1.6 ng/ml, n = 9, P < 0.05). It is suggested that released ghrelin from the gastric mucosa mediates gastric phase III-like contractions, whereas 5-HT released from enterochromaffin cells of the duodenal mucosa mediates intestinal phase III-like contractions via 5-HT4 receptors.

Orienting of Attention

1980 ◽  
Vol 32 (1) ◽  
pp. 3-25 ◽  
Author(s):  
Michael I. Posner
Keyword(s):  
Human Subjects ◽  
Visual Space ◽  
Saccadic Eye Movements ◽  
Brain Injured ◽  
Ballistic Properties ◽  
Normal Human ◽  
High Level ◽  
Relationship Of ◽  
The Relationship ◽  
Attentional Mechanism

Bartlett viewed thinking as a high level skill exhibiting ballistic properties that he called its “point of no return”. This paper explores one aspect of cognition through the use of a simple model task in which human subjects are asked to commit attention to a position in visual space other than fixation. This instruction is executed by orienting a covert (attentional) mechanism that seems sufficiently time locked to external events that its trajectory can be traced across the visual field in terms of momentary changes in the efficiency of detecting stimuli. A comparison of results obtained with alert monkeys, brain injured and normal human subjects shows the relationship of this covert system to saccadic eye movements and to various brain systems controlling perception and motion. In accordance with Bartlett's insight, the possibility is explored that similar principles apply to orienting of attention toward sensory input and orienting to the semantic structures used in thinking.

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