Delta Opioid Receptors Selectively Inhibit Nerve-Driven Contractions in Human Colon | Research

The takeaway

Delta opioid agonists selectively blocked nerve-stimulated colon contractions without affecting spontaneous muscle activity — showing nerve-specific opioid control of human gut.

Nerve-selective inhibition
Delta agonists blocked nerve-stimulated contractions but not spontaneous muscle contractions — a precisely targeted effect

What the researchers found

Delta opioid receptor agonists selectively inhibited nerve-stimulated contractions in human colon tissue without affecting spontaneous contractile activity.

Why it matters

Understanding how opioid receptors control colon nerve signaling helps explain opioid-related constipation and could lead to better treatments for gut motility disorders.

How the study worked

Researchers used superfused strips of human sigmoid colon (both longitudinal and circular muscle). They applied delta opioid agonists and measured spontaneous activity and responses to electrical nerve stimulation.

What this study cannot tell us

In vitro study using human tissue samples. The isolated tissue setting does not fully replicate how the colon functions inside the body with its full nerve supply and hormonal environment.

How to read the evidence

Preliminary — in vitro human tissue study. Uses actual human colon tissue (strong) but in an isolated setting (limited).

When this study was published

Published in 1994 (32 years ago). Human tissue data remains valuable for translational relevance.

The bigger picture

Understanding how different opioid receptor types affect human colon function is essential for managing opioid-induced constipation and developing gut-specific treatments.

Questions still open

Could delta-selective drugs be used to treat specific gut motility disorders?
Do mu and kappa receptors have similar or different selectivity for nerve vs muscle activity?

Common questions

Why only nerve-driven contractions?

Delta opioid receptors appear to be located on nerve endings in the colon rather than on muscle cells. So they only affect contractions that depend on nerve signaling, not the muscle's own rhythmic activity.

How does this relate to constipation from opioids?

By selectively inhibiting nerve-driven contractions, opioids reduce the coordinated propulsive movements that move stool through the colon, while basic muscle tone continues.

Read the original research

Delta-opioid receptor agonists inhibit neuromuscular transmission in human colon.

European journal of pharmacology, 262(1-2), 33-9

View on PubMed ↗

Citation

Chamouard, P; Rohr, S; Meyer, C; Baumann, R; Angel, F. (1994). Delta-opioid receptor agonists inhibit neuromuscular transmission in human colon.. European journal of pharmacology, 262(1-2), 33-9.