Effects of morphine and naloxone on esophageal motility and gastric emptying in man

Abstract

We studied the effect of morphine and naloxone on lower esophageal sphincter pressure, esophageal contraction amplitude, and gastric emptying of solids and liquids in ten normal healthy subjects. Morphine sulfate in a dose of 8 mg intravenous bolus significantly decreased sphincter pressure with a maximum fall of 22.8% of the basal tone. Naloxone, 5 mg intravenous bolus, resulted in a 20% increase in the baseline pressure. There was no change in the esophageal contraction amplitude, duration, or frequency of peristalsis with either morphine or naloxone. Gastric emptying was measured using a dual-isotope technique to simultaneously assess the emptying rates of both solid and liquid meal components. Morphine, 8 mg intravenous bolus, led to a significant inhibition (P less than 0.05) of the gastric emptying of both solids (99mTc sulfur colloid-labeled chicken liver) and liquids (111In DTPA-labeled water). Naloxone, 5 mg intravenous bolus, accelerated the gastric emptying of both solid and liquid components, but this did not achieve statistical significance. These observations suggest that: morphine's inhibitory effect on gastric emptying and lower esophageal sphincter pressure may contribute to its potent emetic properties; the human lower esophageal sphincter and stomach may have opiate receptors and further investigations should be addressed to determining if endogenous opiates play a role in the modulation of sphincter pressure and gastric emptying in humans.

Effects of Age on Esophageal Motility: Use of High-resolution Esophageal Impedance Manometry

“…The premedication history which could be associated with esophageal motility was checked for all subjects within one week before the HRIM test. A study by Mittal et al 16 described that an opioid intravenous bolus significantly decreased low esophageal sphincter pressure which may have opiate receptors. Thus premedication history before manometry was checked including opioid medication.…”

Gastroesophageal reflux in anesthetized dogs: a review

“…Morphine produces emesis when used as a pre-anesthetic. Vomit alone does not determine the possibility of GER during anesthesia, but it is well documented that morphine, when used as pre-anesthetic, increases the risk of GER (Wilson et al ., 2005) since it decreases muscle tone in the LES (Mittal and McCallum, 1986). However, Penagini, and Bianchi (1997) stated that morphine might inhibit the spontaneous relaxation of LES.…”

Achalasia: It Is Not All Black and White

“…Small analyses involving conventional manometry that examined the effects of acute administration of opiates on the LES in healthy subjects produced discrepant findings, with both increased and decreased LES relaxation having been described [16][17][18][19].…”