Differences in the characteristics of opioid receptor binding in the rat and marmoset
Yeadon, M.; Kitchen, I.
Journal of Pharmacy and Pharmacology 40(10): 736-739
1988
ISSN/ISBN: 0022-3573 PMID: 2907546 Document Number: 319371
The density of .mu. and .delta. opioid binding sites in homogenates of rat and marmoset brain was determined using radiolabelled peptides with high receptor selectivity. In addition the affinity of .mu. and .delta. receptor binding of five drugs of the fentanyl series was measured. The ratio of .mu. : .delta. sites was similar within each species but the total receptor binding capacity in the rat was double that of the marmoset. The binding affinities for the .delta. site were dissimilar between the species and supports the hypothesis that the structure of this receptor shows phylogenetic differences. In contrast, .mu. site binding affinity was identical in rat and marmoset.