How does morphine work on colonic motility? An electromyography study in human left and sigmoid colon

Centre Hospitalier Universitaire Sherbrooke, Québec, Canada J1H 5N4
Life Sciences (Impact Factor: 2.7). 03/1986; 38(8):671-6. DOI: 10.1016/0024-3205(86)90580-1
Source: PubMed


The effect of morphine on colonic motility was investigated by recording the colonic myoelectric spiking activity by means of a 50 cm long silastic tube equipped with 4 bipolar AgAgCl ring electrodes fixed at 10 cm intervals that was introduced into the left colon in 8 healthy subjects by flexible sigmoidoscopy. Tracings were obtained for 1 hour in the fasting state and for another 1 hour after i.m. injection of morphine sulphate 0.15 mg/kg. The different types of spike bursts were compared before and after morphine injection. The control tracings showed that the spiking activity of the colon was made of 2 types: 1)- Rhythmic Stationary Spike Bursts (RSB), that were seen at only one electrode site; 2)- Sporadic Bursts, that were either propagating over all 4 electrodes (SPB) or non propagating (SNPB). Injection of morphine was followed by 1)- a considerable increase in the number of RSB from 107 +/- 43 bursts/hour (mean +/- SEM) to 491 +/- 23 bursts/hour; 2)- the complete disappearance of the SPB dropping from 7.3 +/- 2.0 bursts/hour to 0.3 +/- 0.2 bursts/hour; 3)- no significant change in SNPB (from 52 +/- 4 bursts/hour to 57 +/- 5 bursts/hour). These results indicate that 1)- stimulation of colonic smooth muscle activity by morphine seems to result from an increase in the number of rhythmic stationary bursts; 2)- however inhibition of colonic transit may be related to the decrease in the number of sporadic propagating bursts.

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    ABSTRACT: The effects of vasopressin on colonic motility were investigated in 6 healthy subjects and 10 patients with chronic idiopathic constipation. Recordings of the colonic myoelectric spiking activity were performed by means of 50-cm long silastic tube, equipped with four bipolar ring electrodes fixed at 10-cm intervals, which was introduced by flexible colonoscopy into the left colon. Tracing were obtained for 1 h in the fasting state and for another hour after an intramuscular injection of a pharmacological dose of vasopressin (0.3 U/kg). The different types of spike bursts generated by the colonic smooth muscle were compared before and after vasopressin injection. In both controls and patients, the tracing showed (i) rhythmic stationary spike bursts (RSB) that were seen at only one electrode site; and (ii) sporadic bursts that were either propagating over all four electrodes (SPB) or nonpropagating (SNPB). Injection of vasopressin in controls was followed for 30 min by a significant increase in the number of propagating bursts from 2.7 +/- 0.6 (mean +/- SEM) to 5.2 +/- 1.4 bursts (p less than 0.05); RSB and SNPB were not altered by vasopressin. In the constipated patients, the number of propagating bursts during the control period was significantly lower (0.8 +/- 0.2 bursts/30 min) than in the volunteers (p less than 0.05). After vasopressin, there was a significant increase to 3.6 +/- 0.8 bursts/30 min (p less than 0.001); RSB and SNPB also did not show significant alteration after vasopressin. Finally, 4 out of the 10 patients passed stools during the recording session.(ABSTRACT TRUNCATED AT 250 WORDS)
    No preview · Article · Nov 1987 · Canadian Journal of Physiology and Pharmacology
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    No preview · Article · Feb 1988 · Baillière s Clinical Gastroenterology

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