Two affinity ligands, phenacetamido)14beta-hydroxy-7,8-dihydromorphino
ne (4) and ydroxy-7,8-dihydro-N-cyclopropylmehtylnormophinone (5) bind
reversibly to opioid receptors present in bovine caudate membranes an
d photolyse in a range of wavelengths centered about 366 nm to produce
wash-resistant binding to the mu receptor. At these wavelengths very
little if any photodestruction of the mu receptor occurs over the 20 m
inute period of irradiation at 0-degrees-C.