Opioid peptides selectively inhibit the non-cholinergic nerve-driven contraction of airway muscle via prejunctional receptors, with dynorphin being the most potent natural peptide.
Selective for non-cholinergic contractionOpioid peptides blocked the substance P-driven airway constriction while leaving cholinergic contraction largely intact
What the researchers found
Opioid peptides selectively inhibit non-cholinergic excitatory neurotransmission in airways via prejunctional receptors, with dynorphin being the most potent endogenous peptide.
Why it matters
Non-cholinergic nerve signaling contributes to airway constriction in asthma. If opioid peptides naturally regulate this pathway, they could be relevant to understanding and treating asthma.
How the study worked
Guinea pig bronchial strip chains were electrically stimulated. Responses to opioid peptides and direct muscle stimulants (acetylcholine, substance P) were compared.
What this study cannot tell us
In-vitro study in guinea pig airways. Human airway opioid pharmacology may differ. Only electrical stimulation was used, not natural nerve reflexes.
How to read the evidence
Preliminary in-vitro study in guinea pig airways. Provides a clear pharmacological profile but direct human airway relevance needs validation.
When this study was published
Published in 1990. The role of opioid receptors in airway regulation has been further studied, with clinical relevance to respiratory depression from opioid medications.
The bigger picture
Non-cholinergic nerve signaling contributes to airway constriction in conditions like asthma. The finding that opioid peptides naturally regulate this pathway suggests the endogenous opioid system may help protect against excessive airway narrowing. This could explain why stress and mood affect breathing.
Questions still open
- Could opioid-based therapies target airway constriction in asthma?
- Is the airway opioid system impaired in severe asthma patients?
Common questions
How could opioids help with airway problems?
Why is the selectivity important?
Read the original research
Morphine and opioid peptides selectively inhibit the non-cholinergically mediated neurogenic contraction of guinea-pig isolated bronchial muscle.
The Journal of pharmacy and pharmacology, 42(3), 214-6
Citation
Kamikawa, Y; Shimo, Y. (1990). Morphine and opioid peptides selectively inhibit the non-cholinergically mediated neurogenic contraction of guinea-pig isolated bronchial muscle.. The Journal of pharmacy and pharmacology, 42(3), 214-6.