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Dynorphin1-13: interaction with other opiate ligand bindings in vitro
Brain Research
|June 8, 1984
Summary
Dynorphin1-13, a kappa opioid, inhibits morphine
Area of Science:
- Neuroscience
- Pharmacology
- Molecular Biology
Background:
- Dynorphin1-13 exhibits kappa opioid properties in the guinea pig ileum.
- In the brain, dynorphin1-13 lacks analgesic effects but inhibits morphine-induced analgesia.
Purpose of the Study:
- To investigate the mechanism of dynorphin1-13's inhibitory action on morphine in the brain.
- To examine dynorphin1-13's interaction with opiate binding sites in brain membranes.
Main Methods:
- In vitro binding assays using brain membranes.
- Competition assays with various radiolabeled opiate ligands.
Main Results:
- Dynorphin1-13 inhibited the binding of dihydromorphine, D-Ala2-D-Leu5-enkephalin, ethylketocyclazocine (EKC), and naloxone.
- Dynorphin1-13 reduced high-affinity binding sites for all tested ligands.
- Dynorphin1-13 increased the dissociation constant (Kd) for EKC binding.
Conclusions:
- Dynorphin1-13's inhibitory mechanism is complex, not a simple reversible competition.
- The interaction of dynorphin1-13 with opiate receptors differs depending on the specific opiate ligand.