Related Experiment Video
Updated: Jun 12, 2026
09:09
Preparation and Delivery of Protein Microcrystals in Lipidic Cubic Phase for Serial Femtosecond Crystallography
Published on: September 20, 2016
Opioid binding properties in bovine retina.
1Department of Neuropharmacology, Max-Planck-Institut für Psychiatrie, Kraepelinstrasse 2, D-8000 München 40, F.R.G.
Neurochemistry International
|May 22, 2010
Summary
Opiate receptors were identified in bovine retina tissue, showing characteristics similar to those found in the brain. These findings suggest a potential role for these receptors in retinal function.
Area of Science:
- Neuroscience
- Biochemistry
- Ophthalmology
Background:
- Opiate receptors are crucial in pain modulation and reward pathways in the central nervous system.
- Their presence and function in non-neuronal tissues like the retina are less understood.
Purpose of the Study:
- To investigate the presence and characteristics of opiate binding sites in bovine retina.
- To compare retinal opiate receptor properties with those found in the brain.
Main Methods:
- Radioligand binding assays using tritiated dihydromorphine ([(3)H]DHM), D-Ala(2)-D-Leu(5)-enkephalin ([(3)H]DADL), and etorphine.
- Scatchard analysis to characterize binding site density and affinity.
Main Results:
- Saturable binding sites for [(3)H]DHM, [(3)H]DADL, and etorphine were detected in bovine retinal synaptosomes.
- Scatchard analysis indicated two independent binding sites for each ligand.
- Binding site density and affinity, as well as regulation by GTP and sodium, were comparable to brain preparations.
- Selective mu-opioid receptor binding sites for [(3)H]DADL were not detectable, but sites resembling mu-binding sites were observed.
Conclusions:
- Bovine retina possesses opiate binding sites with characteristics similar to central nervous system receptors.
- The findings suggest a potential endogenous opioid system within the retina.
- Further research is warranted to elucidate the specific roles of these receptors in retinal physiology.
Related Concept Videos
01:22Opioid Receptors: Overview
Opioid receptors, including the mu (μ, MOR), delta (δ, DOR), and kappa (κ, KOR) types, belong to the rhodopsin family of G protein-coupled receptors. These receptors are located throughout the central and peripheral nervous systems and in non-neuronal tissues such as macrophages and astrocytes. Opioid receptor ligands can be categorized into agonists or antagonists. Highly selective agonists include [d-Ala2, MePhe4, Gly(ol)5]-enkephalin or DAMGO for MOR, [D-Pen2, D-Pen5]-enkephalin or DPDPE for...
01:23Ophthalmic Drug Delivery Systems
Ophthalmic drug delivery faces major limitations due to poor absorption across the corneal membrane. This process is primarily driven by diffusion and is influenced by two main factors: the physicochemical properties of the drug and tear drainage. Most ophthalmic drugs, such as pilocarpine, epinephrine, atropine, and local anesthetics, are weak bases. They are typically formulated at an acidic pH to enhance chemical stability. However, this leads to high ionization, reducing their ability to...