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Gastric electrical activity and cardiovascular risk factors in relation to autonomic nervous function, hormonal responses, and health-related lifestyles in young men.

BACKGROUND: Electrogastrography (EGG) is the noninvasive recording of gastric myoelectrical activity. The purpose of the present study was to assess associations of EGG with risk factors for cardiovascular disease (CVD), autonomic nervous function, hormonal responses, and health-related lifestyles. METHODS: EGG was measured in 435 Japanese men, aged 24-39 years, who worked at the same company. In addition to anthropometric measurements and blood examinations, power spectral analysis of heart rate variability in low-frequency (LF; 0.04-0.15 Hz) and high-frequency (HF; 0.15-0.40 Hz) bands was conducted. LF/HF and HF were used as the indicators of sympathetic and parasympathetic nervous activity, respectively. Serum cortisol and catecholamine levels were measured as well. RESULTS: In univariate analyses, the EGG frequency was associated positively with the serum high-density lipoprotein (HDL) and cholesterol level (both-P < 0.0001) and negatively with age, body mass index (BMI), serum triglyceride level, fasting blood sugar, and diastolic blood pressure (all P < 0.05). The EGG frequency tended to increase with increases in the HF band (P = 0.10) and was not significantly associated with the LF/HF ratio (P = 0.45). Neither hormonal responses nor health-related lifestyle factors such as smoking and alcohol were significant (all P > 0.05). A multivariate analysis indicated that both the HDL cholesterol level and BMI were independent predictors of EGG frequency (both P < 0.05), after adjusting for the significant effects of age, HF, and other CVD factors. CONCLUSIONS: Slowed EGG frequency appeared to be linked with various CVD risk factors, including obesity and low HDL cholesterol levels, in young men.

Adult↗

In vivo gastric and intestinal slow waves in W/WV mice.

The aim was to investigate whether there are regular gastric and intestinal slow waves in conscious W/WV mice. Eleven W/WV mice and 11 wild-type mice were implanted with two pairs of electrodes in the stomach and small intestine. Gastrointestinal slow waves were recorded both under anesthesia and in the conscious state. Atropine and verapamil were given separately to an additional 10 W/WV mice. Results were as follows. (1) The conscious W/WV mice showed lower rhythmic slow waves in the small intestine (77.1 vs 93.5%; P < 0.001). However, the frequency (10.7 vs 18.8 cpm; P < 0.0001) and the antregrade propagation of intestinal slow waves in W/Wv mice were significantly lower than in the controls. In the stomach, regular slow waves were recorded in both groups, with no difference between the two groups. (2) Anesthesia significantly impaired both gastric and intestinal slow waves in both groups. (3) Atropine and verapamil had no effects on the rhythmicity of intestinal slow waves. We conclude that ICC-MY may not be the sole pacemaker cells for slow waves in the small intestine. There may be some abnormality of smooth muscle cells in W/WV mice that causes a reduction in the frequency, rhythmicity, and antegrade propagation of slow waves.

Anesthesia↗

Electrogastrography in patients with Chagas' disease.

Electrogastrograghy (EGG) was performed in 33 patients with Chagas' disease and in 15 healthy volunteers-control group. The EGG was performed in two different periods: in fasting and postprandial. The EGG was submitted to a continuous spectral analysis. The following parameters were evaluated: % dominant frequency in spectral bands: normogastria (2-4 cpm), bradygastria (1-2 cpm), tachygastria (4-10 cpm) and duod/resp (10-15 cpm). EGG was considered normal if normogastria > 65% in both EGG periods. The chagasic group showed % normogastria significantly lower (basal, P < 0.01), % bradygastria (basal, P = 0.01) and % tachygastria (basal and postprandial, P =.001) significantly higher than the control group. EGG was normal in 14/15 (93%) in control group x 16/33 (53%) in chagasic group (P < 0.05). It was concluded that: 1) the prevalence of gastric dysrhythmias was higher in chagasic patients than in comparison to a control group 2) gastric dysrhythmias may be considered one of the abnormalities presented in the chagasic gastropathy.

Adolescent↗

Inhibitory effects of sildenafil on small intestinal motility and myoelectrical activity in dogs.

Previous studies have shown that sildenafil inhibits the esophageal motility in both humans and animals. The aim of this study was to investigate the effects of sildenafil on intestinal myoelectrical activity and motility. The study was composed of 2 experiments and performed in 7 healthy female dogs with a duodenal cannula 20 cm beyond pylorus (19-26 kg). The first experiment was designed to study the effects of sildenafil on intestinal myoelectrical activity and it included 2 sessions each consisting of 30-minute baseline, 15-minute posttreatment (placebo or 100 mg sildenafil) and 90 minutes after a liquid meal. Intestinal myoelectrical activity was recorded during the entire experiment period. The second experiment was aimed to investigate the effect of sildenafil on intestinal motility and was performed immediately after a solid meal. Intestinal motility was measured by a manometric catheter inserted into the small intestine via the duodenum cannula for 30 minutes at baseline and 60 minutes after sildenafil. Sildenafil significantly reduced the amplitude but had no effect on the frequency and regularity of the intestinal myoelectrical activity. Sildenafil significantly inhibited postprandial intestinal contractions. Although the frequency of the contractions was not altered, the mean area under the curve was significantly reduced during the first 30 minutes (P < .03) and second 30 minutes after sildenafil (P < .03); the power of intestinal contractile activities was also significantly reduced during the first 30 minutes (P < .0004) and second 30 minutes after sildenafil (P < .0003) in comparison with baseline. In conclusion, sildenafil inhibits the amplitude of both intestinal contractile activity and intestinal slow waves.

Animals↗

Roles of interstitial cells of Cajal in intestinal transit and exogenous electrical pacing.

The aims of this study were to investigate the role of interstitial cells of Cajal (ICCs) on small intestinal transit and its responses to exogenous pacing in W/W(v) mice. Eleven W/W(v) mice and their controls implanted with four pairs of gastrointestinal electrodes were used for testing the entrainment of slow waves. Another 20 W/W(v) mice and their controls equipped with a duodenal catheter and one pair of intestinal electrodes were used to test small intestinal transit represented by the geometric center (GC). Results were as follows. (1) The effect of pacing on slow wave frequency was sustained only in controls, and not in W/W(v) mice. (2) Both gastric and intestinal slow waves were completely entrained in controls and W/W(v) mice. Higher energy was required for pacing the stomach than the small intestine. (3) There was no significant difference in small intestinal transit between the controls and the W/W(v) mice (GC: 5.4 vs. 5.5). (4) Pacing showed no effects on small intestinal transit in either wild-type (GC: 5.4 vs. 5.6) or W/W(v) mice (GC: 5.5 vs. 5.7). We conclude that myenteric ICCs may not play an important role in the regulation of small intestinal transit in conscious mice. Gastric and intestinal pacing can be achieved without ICCs.

Animals↗

An evaluation of adult electrogastrography criteria in healthy children.

The current study examined whether electrogastrogram (EGG) recordings obtained from healthy children would be considered normal by standards established for adults and whether EGG patterns differ between children/adolescents and adults. Twenty-eight healthy children (54% females; ages 8-17 years; mean = 12.4 years) were evaluated and compared to 15 healthy adults evaluated previously. EGGs were recorded for 30 min in the fasting state and for 1 hr following a standard meal. For both pediatric and adult participants, there was a significant increase in both the dominant frequency and the dominant power from the pre- to the postprandial period (P < 0.001 for each). Using adult standards, the percentage normal slow waves was > 70% of the recording time in 96% of children in the fasting state and in 100% in the postprandial period. A postprandial power increase was seen in 89% of the children. In conclusion, our data indicate that American Motility Society (AMS) consensus adult criteria for a normal EGG are appropriate to apply to children and adolescents when utilizing methodology and meal challenge similar to those used to establish the adult norms.

Adolescent↗

Small bowel motility: ready for prime time?

The primary function of the small bowel is the absorption of nutrients, and the motor patterns of the healthy bowel are intended to promote that function. The motor patterns of the small bowel are the result of close interaction between the enteric nervous system, extrinsic nerves, regulatory peptides, and the intestinal smooth muscle. The basic electrical rhythm governing intestinal contractions is determined by specialized pacemaker cells called the interstitial cells of Cajal. Diseases affecting any of these components may result in intestinal dysmotility and its associated symptoms. Although transit studies and intestinal manometry are helpful in the diagnosis of dysmotility, our understanding of pathophysiology is hampered by the difficulties involved in obtaining and analyzing intestinal tissue. Treatment of intestinal dysmotility relies on dietary manipulations and nutritional support (enteral or parenteral) because there is no drug therapy that can effectively enhance the propulsive function of the small bowel. Small bowel transplantation remains a life-saving intervention for patients who fail to respond to other therapies.

Gastrointestinal Motility↗

Preservation of continence after ileoanal anastomosis by the coordination of ileal pouch and anal canal motor activity.

Nocturnal incontinence may occur after ileoanal anastomosis and may be related to loss of an effective anal canal pressure barrier during sleep; how pressure and contractions in the proximal bowel influence this barrier is unknown. Our aim was to evaluate the relationship between anal canal pressure and contractions and contractile activity of the pouch in continent subjects after ileal pouch-anal anastomosis (IPAA) and of the rectum in normal controls. A fully ambulatory system for 24-hour pressure recording was used. A flexible transducer catheter was introduced endoscopically so that sensors were at 2, 3, 8, 12, 16, and 24 cm from the anal orifice in 12 healthy controls (7 men, 5 women, mean age: 35 years) and 7 fully continent IPAA patients (4 men, 3 women, mean age: 34 years) more than 12 months postoperatively. Twenty-four hour spontaneous motor activity was stored in a 2.5 megabyte (MB) digital portable recorder. Mean anal canal pressure was calculated, and rectal motor complexes and ileal pouch large pressure waves were characterized. During sleep, resting anal canal pressures were similar in the two groups (72 +/- 12 mm Hg in controls versus 66 +/- 9 mm Hg in IPAA patients [mean +/- standard deviation (SD)], p = NS), but anal canal pressure showed cyclic relaxations (periodicity: 95 +/- 11 min in controls, 54 +/- 18 min in IPAA patients, p less than 0.05), during which the mean pressure trough was 15 +/- 4 mm Hg in controls and 14 +/- 5 mm Hg in IPAA patients (p = NS). In the control patients, during sleep, a mean of six rectal motor complexes were identified (range: 3 to 9). In patients with IPAA, during sleep, a mean of eight large pressure waves per hour were identified (range: 2 to 20). Importantly, in both controls and patients, rectal motor complexes or large pressure waves were always accompanied by rapid return of anal canal pressure from trough to basal values and increased contractile activity. We concluded that, in healthy patients and in continent patients after IPAA, motor activity of the rectum and of the ileal pouch was associated with changes in pressure and contractile activity of the anal canal so that rectal- and neorectal-anal canal pressure gradient, and, in turn, fecal continence were preserved.

Adult↗

Morphine effects on human colonic myoelectric activity in the postoperative period.

Colonic myoelectrical activity was studied in 25 patients, 18 of whom received morphine sulfate, using bipolar electrodes placed in the ascending and descending colon during laparotomy. Baseline myoelectrical activity was recorded daily, then morphine (3 to 15 mg) was administered intravenously, intramuscularly, or epidurally, and recordings continued. Seven activity patterns were observed during recovery from postoperative ileus. During the first 2 postoperative days, morphine at any dose did not affect colon myoelectrical activity. From the third postoperative day on, morphine given intravenously or intramuscularly initiated clusters of short, nonmigrating, phasic spike bursts occurring on each successive slow wave in 14 of 18 patients, which lasted for 30 to 45 minutes. When morphine was administered epidurally, there was no colonic response in any patient. These findings suggest that: (1) morphine intravenously or intramuscularly induces predominantly nonmigrating colonic spike bursts; (2) morphine-induced activity alters the normal pattern of colonic motility during recovery from postoperative ileus; and (3) these phenomena are not due to direct action of morphine on the spinal cord since epidural morphine had no effect.

Colon↗

Erythromycin strengthens the defective lower esophageal sphincter in patients with gastroesophageal reflux disease.

Motilin induces phase III activity of the gastrointestinal tract. Erythromycin has a motilin-like effect on the stomach and significantly increases the lower esophageal sphincter (LES) pressure in normal volunteers. This investigation was performed to evaluate the effects of erythromycin on esophageal function in patients with gastroesophageal reflux disease (GERD). Esophageal manometry was performed in 10 GERD patients before and after intravenous infusion of 500 mg of erythromycin. Values are expressed as mean +/- SEM. LES pressure increased from 13.9 +/- 2.9 mm Hg at baseline to 28.9 +/- 3.6 mm Hg after infusion of erythromycin (p < 0.01). The duration of contractions in the proximal, middle, and distal esophagus was significantly prolonged from 3.5 +/- 0.4 seconds, 3.8 +/- 0.4 seconds, and 4.1 +/- 0.5 seconds to 4.2 +/- 0.2 seconds, 4.6 +/- 0.5 seconds, and 5.6 +/- 0.6 seconds, respectively, after infusion of erythromycin (p < 0.05 for each comparison). Erythromycin did not effect esophageal body contraction amplitude or velocity, or the upper esophageal sphincter. Serum motilin decreased slightly after the administration of erythromycin. We concluded the following: (1) Erythromycin profoundly stimulates the defective LES in patients with GERD. This appears to be a direct motilin agonist-like effect rather than being mediated by release of endogenous motilin. (2) Erythromycin has less effect on the esophageal body, although it does prolong the duration of esophageal contractions.

Erythromycin↗

Abnormal REM sleep in the irritable bowel syndrome.

Motor abnormalities of the small bowel that occur only during the waking state have been reported in the irritable bowel syndrome (IBS), suggesting that central nervous system arousal is a necessary condition for expression of the disorder and that it may reflect inappropriate brain-gut interaction. This possible relationship was explored further by synchronous polysomnography and recording of upper small bowel motility in six healthy subjects and six patients with IBS. During sleep, there was no difference in the patterns of intestinal motility between the two groups. There was no difference between the rapid eye movement (REM) latency or number of REM episodes, but the proportion of REM sleep was markedly increased (36.5% +/- 5.7% vs. 18.2% +/- 5.7%; P less than 0.01) in the IBS group, although the duration of sleep was similar (468 +/- 13 minutes in IBS vs. 444 +/- 10 minutes in controls; P greater than 0.1). Sleep apnea was detected in three of six patients with IBS but was not seen in controls. The data are consistent with the model of IBS as a disorder of brain-gut interaction.

Adult↗

Hyperglycemia induces abnormalities of gastric myoelectrical activity in patients with type I diabetes mellitus.

BACKGROUND/AIMS: Blood glucose concentration has been shown to be an important factor in gastric motility. However, the effect of hyperglycemia on gastric myoelectrical activity has not yet been studied in patients with diabetes. METHODS: Surface electrogastrography was performed in eight patients with type I diabetes mellitus under normoglycemic and hyperglycemic conditions (glucose clamp technique) and in eight normoglycemic control subjects. RESULTS: In the early postprandial state, the frequency of the normal pacemaker rhythm tended to be higher during hyperglycemia than during normoglycemia (3.10 +/- 0.27 vs. 2.92 +/- 0.19 cycle/min; P = 0.061). The frequency decrease that occurs immediately after a meal was found less frequently during hyperglycemia (in 25% vs. 75% of the patients; P = 0.046). Higher harmonics of the 3-cycle/min component, indicating an electrogastrographic waveform change, were found less often during hyperglycemia (in 13% vs. 63% of the patients; P = 0.039). Dysrhythmias (in particular, tachygastrias) were more prevalent during hyperglycemia (40.6% vs. 6.5% of the time; P = 0.028). No differences were found between normoglycemic patients and control subjects. CONCLUSIONS: This study has shown that hyperglycemia is an important factor in the generation of gastric myoelectrical disturbances and tachygastrias in particular.

Adult↗

Bacterial translocation in mesenteric ischemia-reperfusion injury: is dysfunctional motility the link?

The authors previously reported that mesenteric ischemia and reperfusion (I/R) in a chronic newborn piglet model creates dysfunctional intestinal motility. Whether this leads to inadequate bacterial clearance and translocation (BT) through the gastrointestinal tract remains unclear. To test this hypothesis the authors used their chronic piglet model (weight, 3.5 +/- 0.3 kg; age, 18 +/- 4 days; on formula feeding); nonocclusive mesenteric ischemia was induced via reversible pericardial tamponade. Mesenteric flow (SMA Doppler measurement via the retroperitoneal approach) was decreased to 25% +/- 5% of baseline for 300 minutes in the ischemia group (n = 7) and followed by 14 hours of reperfusion in the I/R group (n = 6). Control subjects had a sham operation (n = 7). Mesenteric lymph nodes (MLN), liver (L), spleen (S), ileum, peritoneum, and blood were harvested for blind quantitative microbial analysis. Subjects in the control group had no cultures positive for growth. Eighty-five percent of animals in the ischemia group had positive MLN cultures only (P < .05 v control). All piglets in the I/R group had positive MLN cultures (P < .05 v control), and one third of them manifested bacteremia. Histological examination did not show mucosal disruption in any group. The validity of this model is confirmed by the negative cultures in the control group and by the presence of normal ileal flora in all animals. In the ischemia and I/R groups, MLN cultures were consistently positive with gram-negative bacilli (Escherichia coli and/or Klebsiella pneumoniae). When subjects of the I/R group had more than 1,000 colonies in the MLN, bacteremia with the translocating organisms was also identified.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗

Hormonal control of opossum sphincter of Oddi motility: role of myoneural continuity to duodenum.

Motilin and caerulein are known to affect motility of the sphincter of Oddi (SO) and the gastrointestinal tract. The role of SO-duodenal myoneural continuity in the action of these peptides was studied. Five opossums had translocation of the duodenal papilla into the jejunum, while preserving the blood supply to the SO and duodenum. Serosal electrodes were placed in the SO, duodenum, and jejunum. Five control animals had electrode placement alone. Myoelectric recording was obtained during fasting and after administration of motilin (400 ng/kg) or caerulein (500 ng/kg/hr). Motilin induced premature phase III-like activity in the SO and intestine in controls. After the translocation of the papilla, the spike frequencies during phase II and phase III were significantly lower than in controls, whereas those during phase I and phase IV were not different. Motilin caused premature intestinal phase III and increased SO spike activity. However, the increase in SO spike activity was insufficient to form phase III. Caerulein produced a sustained increase in spike activity in both regions in both groups, but the increase was less in the translocation group than in controls. These data suggest that duodenal activity stimulated by motilin and caerulein participates in the activation of SO motility via intrinsic myoneural pathways.

Animals↗