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Degradation of substance P (SP) and vasoactive intestinal peptide (VIP) by field stimulation
1208 ABSTRACTSOFPAPERS
THE CUTANEOUS ELECTROGASTROGRAM REVEALS IMPORTANT INFORMATION ABOUT GASTRIC MOTIUTY. &&n. R.D. Richards and R.W. McCallum, Unlverslty of Virgin&, Charlottesville,VA The relationship between the cutaneous electrogastrogram (EGG) and gastric motYltyhas not been totally understood. To better interpret the noninvasiveEGG, we simultaneouslyrecorded gastric contractions and EGG’s in 7 normal females j@Dg& The contractions of the stomach and small intestine were recorded by an lntraluminal sdid-state pressure sensor. 3 electrodes were placed on the abdomen over the antrum with a common referencing electrode. The position of the stomach was localized by ultrasound. Three 5DD kcal meals were ingested during the continuous 24-hour recording. R&J& Regular slow wave was recorded in the EGG in all subjects during more than 90% of the entire recording time. 1) The following relationshipwas observed between the contractile strength and the slow wave amplitude: a) Postprandially,both the contractile strength and the slow wave amplitude increased; b) A correlatlon between the MMC In the stomach and the gastric slow wave was observed. I.e., significant amplitude increase of the gastric slow wave during phase Ill. 2) The relationskip in frequency between the contractions and the slow wave was the following: a) During the motor quiescent psrlod. the EGG showed very regular stow waves (about 3 cycles/min, cpm) with constant amplkude. b) The maximum frequency d the regular contraction after eating and during phase Ill was the same as that of the gastrk slow wave. c) Very regular tachygastrlal slow wave (7 cpm) was recorded for 1.5 hrs in one subject who felt severs nausea and no contractions were recorded during that period. d) Bradygastrla (c 1.5 cpm) was usualfy superlmpceed upon the normal gastric slow wave in postprandial EGG’s It was corrdated with strong contractions In the distal antrum and/or the small lntestkm with the same mythm. Conclusion: 1) The regular slow wave with time-varying amplitude in an EGG is associated with regular gastric contractions. 2) The regular slow wave with constant amplitude can be associated with motor quiescence. 3) The relative amplitude increase d the EGG relfects increased contractile strength. 4) Bradygastrla after eating is associated with strong coreractlons in the antrum and/or the rmdl lntestfrm whUe w fs asaoclatedwlthleasarWalcrxWacMlty.
DEGRADATIOB OF SUBSTANCE P (SP) ANDVASOACTIVE INTESTINAL PEPTIDE (VIP) BY FIELD STIEULATION University Department of S. Cipris, 2. Yoskorska B&laster Biomedical Sciences Bamilton Ontario, L8N 325 In studies of the release of SP from the opossum muscularis mucosa, and the release of VIP from the dog circular muscle deep muscular plexus, field stimulation This unexpected caused a decrease in peptide release. result was investigated in experiments in which a braided silk suture (similar to tissue dimensions) was perfused with a solution containing a constant concentration of This sham tissue was field stimulated at the peptide. with tissue, and the same strength as in experiments superfusate was assayed with RIA. Samples were collected To prevent peptide losses due to every two minutes. the whole peptides sticking to the perfusion apparatus, was perfused with peptide for ten to twenty system for RIA and starting to collect samples minutes before BSA was added to the buffer.’ VIP was degraded by In some stimulation of 1Opps and IOpps, 8OV. Ins. experiments SP was degraded by 4Opps 4OV, .Sns. Eoreover in the degree of degradation there vas a difference the electrode arrangements, with some dependant on These results are arrangements causing greater losses. of significance to anyone using superperfusion method to They indicate that superfusion study peptide release. studies in which peptide release is monitored are subject to artifactual degradation of the peptides owing to field used to release regularly stimulation with parameters neuropeptides. Supported by MRC of Canada.
October 1990
TOPOGRAPHIC STUDIESOF ESOPBAGZAL MOTILITY: OBSERVATIONS IN PATIENTS WITH DOUBLE-PEAKED WAVES. R.E. Clause, A. Staisno, D.M. Feeney, L.B. Weinstock. Washington University School of Medicine, St. Louis Double-peaked contraction vaVes are often observed during esophageal manometry, and the contraction events responsible for their occurrence are poorly understood. Esophageal location of these waves was determined in 50 subjec,ts,end the spatial relationship of double-peaked waves to neighboring contraction events was exemined in 8 subjects using a topographic method of studying esophageal peristalsis. The topographic plots were constructed frorqconventional manometric waves. A typical (median) post:deglutitive wave' was established for each an of esophageal length, and these waves were spatially interconnected using a computerized gridding and plotting system. Plots from subjects with double-peaked waves were compared to similarly-derived plots from 8 normal Volunteers. RESULTS: 690 double-peeked waVes were detected. These waves were clustered in the distal esophagus, the center of their distribution being 6.3 +2.5 cm above the lower esophageal sphincter. This location was near one of 2 pressure troughs found in contour plots from the distal esophagus in the control subjects (middle trough: 7.5 50.9 cm above LES). Topographic studies showed that the waves represented disrupted connection of the first and second contraction segments in the distal esophagus across this middle trough. Unusual prominence of either the distal component of the'first segment o?zproximal component of the second segment could have been responsible for the findings. CONCLUSIONS: These results demonstrate that double-peaked contraction waves detected by conventional esophageal msncmetry likely represent abnormal alignment of contraction segments in the distal esophagus. Topographic studies of esophageal peristalsis are useful in determining these spa&al relationships.
REPRODUCIBILITY,OF THE RAPID PULL-THRGUGH (RPT) TECHNIQUE FOR CATEGORIZING LCZH3RESOPBAGEAL SPHINCIER (LZS) PRESSURE. A. Staiano and R.E. Clause. Nashington University School of Nedicine, St. Louis, MD Interstudy variability of the techniques used for measuring basal LES pressure is rewgnized, but the ability of any technique to reproducibly identify abnormal values has not been studied. We examined duplicate RPTs in 250 consecutive patients to determine RPT reproducibility for categorizing LZZpre-asinto normal, hypertensive, or hypotensive categories. RPTe were performed with a triple@aen catheter during suspended respiration using a withdrawal rate of 1 cm/s and were repeated after 1 min. Measurements over gastric baseline were taken for each 1-n and averaged for LES pressure. RZSULTS: For all subjects, mean IES pressure was not different for the 2 studies: 25.3 3.0 vs 26.2 21.0 nsaHg,,but the correlation was only modest (R=O.73). Interstudy Variance averaged 7.9 20-6 mm Hg. Reproducibility of categorization was 92% (230/250) and was best for subjects with normal (170/179; 95%) or hypotensive (24/26; 92%) values on the first study (for hypertensivea: 36/45; 80%). Interstudy variance was least for the hypotensive +oup (1.8 +0.21 and greatest for the hypertensive group (16.4 +1.91. Likewise, the range of indipidual lumen values comprising the LE.9pressure wus least for hypotensive subjects (4.7 $I.71 and greatest for hypertensive subjects (32.5 22.6). CONCLUSIONS: Despite its interstudy variance, the RPT can reproducibly categorize LZS pressure in>90% of cases. Hypotensive and normotensive LES pressures are least influenced by variability of the technique. Hypertensive LE.9on a single RPT is least reliable and is associated with the widest range of individual lumen values. Technical factors, e.g., diaphragmatic contraction, may most significantly contribute to variability in the subset with hypertensive LZS.
THE CUTANEOUS ELECTROGASTROGRAM REVEALS IMPORTANT INFORMATION ABOUT GASTRIC MOTIUTY. &&n. R.D. Richards and R.W. McCallum, Unlverslty of Virgin&, Charlottesville,VA The relationship between the cutaneous electrogastrogram (EGG) and gastric motYltyhas not been totally understood. To better interpret the noninvasiveEGG, we simultaneouslyrecorded gastric contractions and EGG’s in 7 normal females j@Dg& The contractions of the stomach and small intestine were recorded by an lntraluminal sdid-state pressure sensor. 3 electrodes were placed on the abdomen over the antrum with a common referencing electrode. The position of the stomach was localized by ultrasound. Three 5DD kcal meals were ingested during the continuous 24-hour recording. R&J& Regular slow wave was recorded in the EGG in all subjects during more than 90% of the entire recording time. 1) The following relationshipwas observed between the contractile strength and the slow wave amplitude: a) Postprandially,both the contractile strength and the slow wave amplitude increased; b) A correlatlon between the MMC In the stomach and the gastric slow wave was observed. I.e., significant amplitude increase of the gastric slow wave during phase Ill. 2) The relationskip in frequency between the contractions and the slow wave was the following: a) During the motor quiescent psrlod. the EGG showed very regular stow waves (about 3 cycles/min, cpm) with constant amplkude. b) The maximum frequency d the regular contraction after eating and during phase Ill was the same as that of the gastrk slow wave. c) Very regular tachygastrlal slow wave (7 cpm) was recorded for 1.5 hrs in one subject who felt severs nausea and no contractions were recorded during that period. d) Bradygastrla (c 1.5 cpm) was usualfy superlmpceed upon the normal gastric slow wave in postprandial EGG’s It was corrdated with strong contractions In the distal antrum and/or the small lntestkm with the same mythm. Conclusion: 1) The regular slow wave with time-varying amplitude in an EGG is associated with regular gastric contractions. 2) The regular slow wave with constant amplitude can be associated with motor quiescence. 3) The relative amplitude increase d the EGG relfects increased contractile strength. 4) Bradygastrla after eating is associated with strong coreractlons in the antrum and/or the rmdl lntestfrm whUe w fs asaoclatedwlthleasarWalcrxWacMlty.
DEGRADATIOB OF SUBSTANCE P (SP) ANDVASOACTIVE INTESTINAL PEPTIDE (VIP) BY FIELD STIEULATION University Department of S. Cipris, 2. Yoskorska B&laster Biomedical Sciences Bamilton Ontario, L8N 325 In studies of the release of SP from the opossum muscularis mucosa, and the release of VIP from the dog circular muscle deep muscular plexus, field stimulation This unexpected caused a decrease in peptide release. result was investigated in experiments in which a braided silk suture (similar to tissue dimensions) was perfused with a solution containing a constant concentration of This sham tissue was field stimulated at the peptide. with tissue, and the same strength as in experiments superfusate was assayed with RIA. Samples were collected To prevent peptide losses due to every two minutes. the whole peptides sticking to the perfusion apparatus, was perfused with peptide for ten to twenty system for RIA and starting to collect samples minutes before BSA was added to the buffer.’ VIP was degraded by In some stimulation of 1Opps and IOpps, 8OV. Ins. experiments SP was degraded by 4Opps 4OV, .Sns. Eoreover in the degree of degradation there vas a difference the electrode arrangements, with some dependant on These results are arrangements causing greater losses. of significance to anyone using superperfusion method to They indicate that superfusion study peptide release. studies in which peptide release is monitored are subject to artifactual degradation of the peptides owing to field used to release regularly stimulation with parameters neuropeptides. Supported by MRC of Canada.
October 1990
TOPOGRAPHIC STUDIESOF ESOPBAGZAL MOTILITY: OBSERVATIONS IN PATIENTS WITH DOUBLE-PEAKED WAVES. R.E. Clause, A. Staisno, D.M. Feeney, L.B. Weinstock. Washington University School of Medicine, St. Louis Double-peaked contraction vaVes are often observed during esophageal manometry, and the contraction events responsible for their occurrence are poorly understood. Esophageal location of these waves was determined in 50 subjec,ts,end the spatial relationship of double-peaked waves to neighboring contraction events was exemined in 8 subjects using a topographic method of studying esophageal peristalsis. The topographic plots were constructed frorqconventional manometric waves. A typical (median) post:deglutitive wave' was established for each an of esophageal length, and these waves were spatially interconnected using a computerized gridding and plotting system. Plots from subjects with double-peaked waves were compared to similarly-derived plots from 8 normal Volunteers. RESULTS: 690 double-peeked waVes were detected. These waves were clustered in the distal esophagus, the center of their distribution being 6.3 +2.5 cm above the lower esophageal sphincter. This location was near one of 2 pressure troughs found in contour plots from the distal esophagus in the control subjects (middle trough: 7.5 50.9 cm above LES). Topographic studies showed that the waves represented disrupted connection of the first and second contraction segments in the distal esophagus across this middle trough. Unusual prominence of either the distal component of the'first segment o?zproximal component of the second segment could have been responsible for the findings. CONCLUSIONS: These results demonstrate that double-peaked contraction waves detected by conventional esophageal msncmetry likely represent abnormal alignment of contraction segments in the distal esophagus. Topographic studies of esophageal peristalsis are useful in determining these spa&al relationships.
REPRODUCIBILITY,OF THE RAPID PULL-THRGUGH (RPT) TECHNIQUE FOR CATEGORIZING LCZH3RESOPBAGEAL SPHINCIER (LZS) PRESSURE. A. Staiano and R.E. Clause. Nashington University School of Nedicine, St. Louis, MD Interstudy variability of the techniques used for measuring basal LES pressure is rewgnized, but the ability of any technique to reproducibly identify abnormal values has not been studied. We examined duplicate RPTs in 250 consecutive patients to determine RPT reproducibility for categorizing LZZpre-asinto normal, hypertensive, or hypotensive categories. RPTe were performed with a triple@aen catheter during suspended respiration using a withdrawal rate of 1 cm/s and were repeated after 1 min. Measurements over gastric baseline were taken for each 1-n and averaged for LES pressure. RZSULTS: For all subjects, mean IES pressure was not different for the 2 studies: 25.3 3.0 vs 26.2 21.0 nsaHg,,but the correlation was only modest (R=O.73). Interstudy Variance averaged 7.9 20-6 mm Hg. Reproducibility of categorization was 92% (230/250) and was best for subjects with normal (170/179; 95%) or hypotensive (24/26; 92%) values on the first study (for hypertensivea: 36/45; 80%). Interstudy variance was least for the hypotensive +oup (1.8 +0.21 and greatest for the hypertensive group (16.4 +1.91. Likewise, the range of indipidual lumen values comprising the LE.9pressure wus least for hypotensive subjects (4.7 $I.71 and greatest for hypertensive subjects (32.5 22.6). CONCLUSIONS: Despite its interstudy variance, the RPT can reproducibly categorize LZS pressure in>90% of cases. Hypotensive and normotensive LES pressures are least influenced by variability of the technique. Hypertensive LE.9on a single RPT is least reliable and is associated with the widest range of individual lumen values. Technical factors, e.g., diaphragmatic contraction, may most significantly contribute to variability in the subset with hypertensive LZS.