Related Experiment Videos
An endogenous ligand for the sigma opioid binding site
P C Contreras1, D A DiMaggio, T L O'Donohue
1Experimental Therapeutics Branch, National Institute of Neurological and Communicative Disorders and Stroke, Bethesda, Maryland 20892.
Synapse (New York, N.Y.)
|January 1, 1987
Summary
Researchers found a distinct endogenous peptide in pigs that binds to sigma opioid receptors, not phencyclidine (PCP) receptors. This suggests separate receptors and ligands for PCP and sigma opioids.
Area of Science:
- Neuroscience
- Pharmacology
- Biochemistry
Background:
- Phencyclidine (PCP) and sigma opioids share psychotomimetic effects, suggesting a common receptor.
- Recent studies show binding differences between PCP and SKF 10,047 (a sigma opioid agonist), implying distinct receptors.
Purpose of the Study:
- To investigate the existence of separate endogenous ligands for PCP and sigma opioid receptors.
- To isolate and characterize a potential endogenous ligand for sigma opioid receptors.
Main Methods:
- Utilized porcine brains, known for isolating PCP receptor ligands.
- Isolated a factor that inhibited [3H]-(+)SKF 10,047 binding but not [3H]-PCP binding.
- Tested the protein/peptide nature of the factor using pronase (a peptidase).
Main Results:
- An endogenous factor was isolated from porcine brain fractions.
- This factor specifically inhibited the binding of sigma opioid agonists ([3H]-(+)SKF 10,047).
- The factor's activity was abolished by pronase, indicating it is a peptide or protein.
Conclusions:
- Evidence suggests the existence of a distinct endogenous ligand for sigma opioid receptors.
- This endogenous ligand differs from the previously identified ligand for PCP receptors.
- Supports the hypothesis of separate receptors for phencyclidine and sigma opioids.