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Does circular muscle of the canine colon produce prolonged contractions?
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ABSTRACTS OF PAPERS
EFFECT OF SINGLE AND MULTIPLE SUCCESSIVE PULSES ON MEMBRANE POTENTIAL IN ESOPHAGEAL CIRCULAR MUSCLE. Jeffrey Crist and Raj K. Goyal. Harvard Digestive Diseases Center, HarvardThorndike Laboratory, Charles A. Dana Research Institute, GI Division, Beth Israel Hospital. Boston, MA 02215 Studies were performed in strips of circular smooth muscle taken from the opossum esophagus 8-9 cm above the lower esophageal sphincter. Membrane potential changes in response to tranamural stimulation (100 V, 1 msec pulses) were recorded using standard intracellular recording techniques. Both single pulses and 5 set trains of aucceaaive pulses (2-10 He) produced initial hyperpolarization followed by recovery and overshooting of the baseline membrane potential within the first 3 aec after the onset of the stimulus. After termination of a train of pulses there waa a slight membrane hyperpolarization followed by depolarization and spikes. With both single pulses and trains of pulses the latency of hyperpolariaation was 165 f 8 msec (mean + S.E., n-4). The maximal amplitude of hyperpolarieation was 8.7 t 0.4 mV with single pulsea and 13.6 f 0.7 mV with trains of pulses. The time to reach maximal hyperpolariaation was 609 ? 11 msec for single pulses and 900 + 50 msec for multiple successive pulses. The recovery to baseline occurred at 1140 t 20 maec with single pulses and 2200 2 100 msec with trains of pulses. The amplitude of the depolarization above baseline membrane potential was 3.8 ?I0.2 mV for single pulses and 3.2 2 0.6 mV (during the stimulus train) for multiple successive pulses. Atropine (10 uM) had no effect on the membrane potential responses to a single pulse and the amplitude and time at which maximum hyperpolarisation occurred with multiple pulses. However, atropine significantly depressed the rate and degree of recovery depolarization during a train of pulses. After atropine the membrane potential failed to recover to baseline during multiple successive pulses. These studies show that cholinergic excitatory nerves play a role in the recovery of membrane potential from initial hyperpolarisation in response to multiple auccesaive pulses but not in response to a single pulse.
EARLY APPEARANCE OF LATERAL PHARYNGEAL OUTPOUCHINGS: SIGNIFICANT ASSOCIATION WITH DYSPHAGIA. AN INDICATION OF PHARYNGEAL DYSFUNCTION? D.J. Curtis, D.F. Cruesa. Depta. of Radioloev and Preventive Medicine. The George Washington University, Washington, DC, and Uniformed Services University of the Health Sciences, Bethesda, MD. Videopharyngeal fluoroscopic timings of individuals with dysphagia were compared with timings from individuals without dysphagia to determine if abnormal movements were associated with dysphagia. Anteroposterior and lateral swallow fluoroscopies were videorecorded on 188 unselected volunteers. Sixty-three (63) events were blindly timed as reported by Curtis et al. A symptomatology questionnaire was completed by each volunteer. All data were computerized and timings compared by student T-test. Fifty (50) individuals were determined to qualify as having dysphagia, while 138 were asymptomatic. Sixteen (16) lateral pharyngeal outpouchinga were seen in the dysphagia volunteers, 71 were noted in the asymptomatic individuals. The outpouchings appeared at an average of 511 msec (p<.Ol) on the right and at 529 msec (p<.Ol) on the left in symptomatic volunteers just after oral delivery of the bolus into the pharynx as compared to 766 msec on the right and 788 on the left during mid pharyngeal swallow in asymptomatic individuals. The outpouchings disappeared on the right on the average at 763 msec (pc .005) and at 832 msec (p< .Ol) on the left during mid pharyngeal swallow in symptomatic volunteers, while they disappeared at 1054 msec on the right and 1143 msec on the left during pharyngeal relaxation in asymptomatic volunteers. No other timing event was delayed nor event duration prolonged when the two groups were compared. This observation suggests intrapharyngeal pressures may be elevated earlier in dysphagic individuals and that pharyngeal tone may be greater or inner longitudinal muscles may be contracting earlier than seen in asymptomatic individuals.
GASTROENTEROLOGY Vol. 91, No. 4
THE NUTCRACKER ESOPHAGUS (NC). LONG-TERM CLINICAL FOLLOWUP (F/U). CB Dalton, LA Bradley, DO Caatell, JE Richter. Bowman Gray School of Medicine, Winston-Salem, NC. Little is known about the natural history of NC, an eaophageal motility disorder (EMD) associated with cheat pain and high amplitude-peristaltic contractions. We followed 20 NC pts (12M, 8F; x age 49.6 yrs; 7 Tensilon+) for x 16.9 mos (range 7-26). F/U Included: Initial esophageal manometry (EM) and 2 F/U studies assessing distal amplitude (Amp) and duration (Dur). Pressures compared with Chest Pain Index (CPI) [severity (l-10) x frequency] obtained from patients' diaries over 2 weeks prior to EM. Use of prescription drugs and health care facilities (HCF) for chest pain compared for 6 mos before 1st EM and 3rd EM. 17 pts given Millon Behavioral Health Inventory (MBHI) and Diagnostic Interview Scale (DIS) to assess prevalence of emotional disorders. Statiatics: t-test, linear regression, multiple regression analysis. RESULTS: Pressures and CPI decreased over time (xtSE): Dur(sec) CPI Amp(SmHg) 1st EM: 10.3+2.0\ 212+11\ 5.0?0.3\ lBS+ll p<.OO5 4.620.3 pd.01 2nd EM: 6.021.9 p<.OO5 3rd EM: 145+13/~ 4.0t0.3/3.2+0.8.'~ There was poor correlation between Amp/CPI initially (r-.06), at 2nd EM (r=.07) and 3rd EM (r=.22); similar results for Dur/CPI. Use of HCF dramatically decreased: 3.220.5 (?SE) visits before 1st EM to 0.6t0.3 visits at 3rd EM, p<.OOOl. Drug use also decreased: 1.220.2 drugs to 0.4tO.2, p<.Ol. Motility changes: 2/20 deteriorated into 1) diffuse spasm; 2) nonspecific EMD with 10% retrograde and 10% simultaneous contractions. Psychological tests: 11/17(65%) had either abnormal DIS or MBHI and high scores 070) on the latter inventory predicted poor long-term outcome. CONCLUSIONS: 1) Pts with NC had a significant decrease in cheat pain, and the use of HCF and medications after x F/U 22.1 mos 2) x Amp and Dur also significantly decreased although there was no linear correlation between pressure and pain. 3) Emotional disorders are common in NC pts (65%) and may predict a poor outcome. 4) Reassurance about cause of CP and decreasing stress factors may be important therapy. 5) Some NC pts will deteriorate into other EMU confirming it is part of spectrum of disease.
DOES CIRCUL6R MUSCLJI OF THE CANINE COLON PRODUCE PROLONGED CONTRACTIONS? L Debaki, Y J Kingma, K L Institute e Surgical-Medical Research and Departments of Electrical Engineering and Surgery, University of Alberta, Edmonton, Alberta, Canada. Peristalsis in the intact colon is associated with prolonged contractions (PC). Of the two colonic muscles, the circular muscle is assumed to produce rhythmic synchronous low-amplitude contractions with (RC) electrical slow-wave frequencies (4-8 cpn), whereas the longitudidnal muscle is shown to generate forceful PC which span several RC cycles. This in-vitro study was undertaken to determine whether circular muscle could produce PC. The investigations comprised two groups of* specimens. In the first group, tubular whole segments, 15 cm long, were used. The contractility of the preparations was monitored with strain-gauge transducers sutured to the circular layer with the sensitive axis in circular second direction. In the flat group. preparations (0.5 x 2.5 cm) of intact muscle-wall strips cut in circular direction and isolated circular muscle The contractility waa monitored with were employed. Grass force-displacement transducers. The tubular segments displayed spontaneous PC with occasionally superimposed RC. Intact muscle-wall strips demonstrated spontaneous RC and PC. Isolated circular muscle exhibited only apon~~eoua RC, but when pharmacological electrical (field oscillations (carbachol 1.7 x 10 M), to simulate spike bursts seen in longitudinal muscle) and mechanical (pinching) stimuli were employed, PC occurred in this tissue. We conclude that circular muscle appears capable of producing PC when in contact with longitudinal muscle and myenteric ganglia or when subjected to cholinergic, electrical and mechanical stimulation.
ABSTRACTS OF PAPERS
EFFECT OF SINGLE AND MULTIPLE SUCCESSIVE PULSES ON MEMBRANE POTENTIAL IN ESOPHAGEAL CIRCULAR MUSCLE. Jeffrey Crist and Raj K. Goyal. Harvard Digestive Diseases Center, HarvardThorndike Laboratory, Charles A. Dana Research Institute, GI Division, Beth Israel Hospital. Boston, MA 02215 Studies were performed in strips of circular smooth muscle taken from the opossum esophagus 8-9 cm above the lower esophageal sphincter. Membrane potential changes in response to tranamural stimulation (100 V, 1 msec pulses) were recorded using standard intracellular recording techniques. Both single pulses and 5 set trains of aucceaaive pulses (2-10 He) produced initial hyperpolarization followed by recovery and overshooting of the baseline membrane potential within the first 3 aec after the onset of the stimulus. After termination of a train of pulses there waa a slight membrane hyperpolarization followed by depolarization and spikes. With both single pulses and trains of pulses the latency of hyperpolariaation was 165 f 8 msec (mean + S.E., n-4). The maximal amplitude of hyperpolarieation was 8.7 t 0.4 mV with single pulsea and 13.6 f 0.7 mV with trains of pulses. The time to reach maximal hyperpolariaation was 609 ? 11 msec for single pulses and 900 + 50 msec for multiple successive pulses. The recovery to baseline occurred at 1140 t 20 maec with single pulses and 2200 2 100 msec with trains of pulses. The amplitude of the depolarization above baseline membrane potential was 3.8 ?I0.2 mV for single pulses and 3.2 2 0.6 mV (during the stimulus train) for multiple successive pulses. Atropine (10 uM) had no effect on the membrane potential responses to a single pulse and the amplitude and time at which maximum hyperpolarisation occurred with multiple pulses. However, atropine significantly depressed the rate and degree of recovery depolarization during a train of pulses. After atropine the membrane potential failed to recover to baseline during multiple successive pulses. These studies show that cholinergic excitatory nerves play a role in the recovery of membrane potential from initial hyperpolarisation in response to multiple auccesaive pulses but not in response to a single pulse.
EARLY APPEARANCE OF LATERAL PHARYNGEAL OUTPOUCHINGS: SIGNIFICANT ASSOCIATION WITH DYSPHAGIA. AN INDICATION OF PHARYNGEAL DYSFUNCTION? D.J. Curtis, D.F. Cruesa. Depta. of Radioloev and Preventive Medicine. The George Washington University, Washington, DC, and Uniformed Services University of the Health Sciences, Bethesda, MD. Videopharyngeal fluoroscopic timings of individuals with dysphagia were compared with timings from individuals without dysphagia to determine if abnormal movements were associated with dysphagia. Anteroposterior and lateral swallow fluoroscopies were videorecorded on 188 unselected volunteers. Sixty-three (63) events were blindly timed as reported by Curtis et al. A symptomatology questionnaire was completed by each volunteer. All data were computerized and timings compared by student T-test. Fifty (50) individuals were determined to qualify as having dysphagia, while 138 were asymptomatic. Sixteen (16) lateral pharyngeal outpouchinga were seen in the dysphagia volunteers, 71 were noted in the asymptomatic individuals. The outpouchings appeared at an average of 511 msec (p<.Ol) on the right and at 529 msec (p<.Ol) on the left in symptomatic volunteers just after oral delivery of the bolus into the pharynx as compared to 766 msec on the right and 788 on the left during mid pharyngeal swallow in asymptomatic individuals. The outpouchings disappeared on the right on the average at 763 msec (pc .005) and at 832 msec (p< .Ol) on the left during mid pharyngeal swallow in symptomatic volunteers, while they disappeared at 1054 msec on the right and 1143 msec on the left during pharyngeal relaxation in asymptomatic volunteers. No other timing event was delayed nor event duration prolonged when the two groups were compared. This observation suggests intrapharyngeal pressures may be elevated earlier in dysphagic individuals and that pharyngeal tone may be greater or inner longitudinal muscles may be contracting earlier than seen in asymptomatic individuals.
GASTROENTEROLOGY Vol. 91, No. 4
THE NUTCRACKER ESOPHAGUS (NC). LONG-TERM CLINICAL FOLLOWUP (F/U). CB Dalton, LA Bradley, DO Caatell, JE Richter. Bowman Gray School of Medicine, Winston-Salem, NC. Little is known about the natural history of NC, an eaophageal motility disorder (EMD) associated with cheat pain and high amplitude-peristaltic contractions. We followed 20 NC pts (12M, 8F; x age 49.6 yrs; 7 Tensilon+) for x 16.9 mos (range 7-26). F/U Included: Initial esophageal manometry (EM) and 2 F/U studies assessing distal amplitude (Amp) and duration (Dur). Pressures compared with Chest Pain Index (CPI) [severity (l-10) x frequency] obtained from patients' diaries over 2 weeks prior to EM. Use of prescription drugs and health care facilities (HCF) for chest pain compared for 6 mos before 1st EM and 3rd EM. 17 pts given Millon Behavioral Health Inventory (MBHI) and Diagnostic Interview Scale (DIS) to assess prevalence of emotional disorders. Statiatics: t-test, linear regression, multiple regression analysis. RESULTS: Pressures and CPI decreased over time (xtSE): Dur(sec) CPI Amp(SmHg) 1st EM: 10.3+2.0\ 212+11\ 5.0?0.3\ lBS+ll p<.OO5 4.620.3 pd.01 2nd EM: 6.021.9 p<.OO5 3rd EM: 145+13/~ 4.0t0.3/3.2+0.8.'~ There was poor correlation between Amp/CPI initially (r-.06), at 2nd EM (r=.07) and 3rd EM (r=.22); similar results for Dur/CPI. Use of HCF dramatically decreased: 3.220.5 (?SE) visits before 1st EM to 0.6t0.3 visits at 3rd EM, p<.OOOl. Drug use also decreased: 1.220.2 drugs to 0.4tO.2, p<.Ol. Motility changes: 2/20 deteriorated into 1) diffuse spasm; 2) nonspecific EMD with 10% retrograde and 10% simultaneous contractions. Psychological tests: 11/17(65%) had either abnormal DIS or MBHI and high scores 070) on the latter inventory predicted poor long-term outcome. CONCLUSIONS: 1) Pts with NC had a significant decrease in cheat pain, and the use of HCF and medications after x F/U 22.1 mos 2) x Amp and Dur also significantly decreased although there was no linear correlation between pressure and pain. 3) Emotional disorders are common in NC pts (65%) and may predict a poor outcome. 4) Reassurance about cause of CP and decreasing stress factors may be important therapy. 5) Some NC pts will deteriorate into other EMU confirming it is part of spectrum of disease.
DOES CIRCUL6R MUSCLJI OF THE CANINE COLON PRODUCE PROLONGED CONTRACTIONS? L Debaki, Y J Kingma, K L Institute e Surgical-Medical Research and Departments of Electrical Engineering and Surgery, University of Alberta, Edmonton, Alberta, Canada. Peristalsis in the intact colon is associated with prolonged contractions (PC). Of the two colonic muscles, the circular muscle is assumed to produce rhythmic synchronous low-amplitude contractions with (RC) electrical slow-wave frequencies (4-8 cpn), whereas the longitudidnal muscle is shown to generate forceful PC which span several RC cycles. This in-vitro study was undertaken to determine whether circular muscle could produce PC. The investigations comprised two groups of* specimens. In the first group, tubular whole segments, 15 cm long, were used. The contractility of the preparations was monitored with strain-gauge transducers sutured to the circular layer with the sensitive axis in circular second direction. In the flat group. preparations (0.5 x 2.5 cm) of intact muscle-wall strips cut in circular direction and isolated circular muscle The contractility waa monitored with were employed. Grass force-displacement transducers. The tubular segments displayed spontaneous PC with occasionally superimposed RC. Intact muscle-wall strips demonstrated spontaneous RC and PC. Isolated circular muscle exhibited only apon~~eoua RC, but when pharmacological electrical (field oscillations (carbachol 1.7 x 10 M), to simulate spike bursts seen in longitudinal muscle) and mechanical (pinching) stimuli were employed, PC occurred in this tissue. We conclude that circular muscle appears capable of producing PC when in contact with longitudinal muscle and myenteric ganglia or when subjected to cholinergic, electrical and mechanical stimulation.