Effects of some opiates and opioid peptide eyedrops on ocular melatonin regulation in rabbits.
Levels of melatonin in rabbit eye tissues were detected by radioimmunoassay. Solutions of met-enkephalin, leu-enkephalin, alpha-endorphin and beta-endorphin were given topically. Met-Enkephalin and alpha-endorphin lowered levels of melatonin in the iris, iris root-ciliary body, retina and choroid; leu-enkephalin raised levels in the retina and lowered them in other tissues. beta-Endorphin only lowered levels in the iris root-ciliary body. DAGO (a mu agonist) given i.v. lowered levels of melatonin in the iris, iris root-ciliary body and retina. The delta and sigma agonists given i.v. only lowered levels in the iris root-ciliary body, and a kappa agonist given i.v. raised levels in the ciliary body. No opiate binding sites could be detected in the rabbit iris or iris root-ciliary body for any class of receptor. Our data suggest opioids may be useful for treating glaucoma.
Rohde
B H
BH
Department of Medical Pharmacology and Toxicology, TAMU College of Medicine, College Station, Tex. 77843.
Zhu
M
M
el Messiry
S
S
Chiou
G C
GC
D019900:3,4-Dichloro-N-methyl-N-(2-(1-pyrrolidinyl)-cyclohexyl)-benzeneacetamide, (trans)-Isomer; D000818:Animals; D001665:Binding Sites; D004723:Endorphins / Q000008:administration & dosage / Q000494:pharmacology*; D005260:Female; D008550:Melatonin / Q000378:metabolism*; D009883:Ophthalmic Solutions; D010620:Phenazocine / Q000008:administration & dosage / Q000031:analogs & derivatives / Q000494:pharmacology; D011759:Pyrrolidines / Q000008:administration & dosage / Q000494:pharmacology; D011817:Rabbits; D011863:Radioimmunoassay; D011957:Receptors, Opioid / Q000378:metabolism; D012160:Retina / Q000187:drug effects / Q000378:metabolism*; D014602:Uvea / Q000187:drug effects / Q000378:metabolism*
D004723:Endorphins; D009883:Ophthalmic Solutions; D011759:Pyrrolidines; D011957:Receptors, Opioid; D019900:3,4-Dichloro-N-methyl-N-(2-(1-pyrrolidinyl)-cyclohexyl)-benzeneacetamide, (trans)-Isomer; C012134:SK&F 10047; D010620:Phenazocine; D008550:Melatonin