Quantitative autoradiography of (/sup 3/H)CTOP binding to mu opioid receptors in rat brain

Journal Article · Fri Jan 01 04:00:00 EST 1988 · Life Sci.; (United States)

DOI:https://doi.org/10.1016/0024-3205(88)90322-0· OSTI ID:7253544

Hawkins, K N; Knapp, R J; Gehlert, D R; Lui, G K; Yamamura, M S; Roeske, L C; Hruby, V J; Yamamura, H I

(/sup 3/H)H-D-Phe-Cys-Tyr-D-Trp-Orn-Thr-Pen-Thr-NH2 ((/sup 3/H)CTOP), a potent and highly selective mu opioid antagonist, was used to localize the mu receptors in rat brain by light microscopic autoradiography. Radioligand binding studies with (/sup 3/H)CTOP using slide-mounted tissue sections of rat brain produced a Kd value of 1.1 nM with a Bmax value of 79.1 fmol/mg protein. Mu opioid agonists and antagonists inhibited (/sup 3/H)CTOP binding with high affinity (IC50 values of 0.2-2.4nM), while the delta agonist DPDPE, delta antagonist ICI 174,864, and kappa agonist U 69,593 were very weak inhibitors of (/sup 3/H)CTOP binding. Light microscopic autoradiography of (/sup 3/H)CTOP binding sites revealed regions of high density and regions of moderate labeling. The cerebral cortex showed a low density of (/sup 3/H)CTOP binding.

• Research Organization: Univ. of Arizona Health Sciences Center, Tucson, (USA)
• OSTI ID: 7253544
• Journal Information: Life Sci.; (United States), Journal Name: Life Sci.; (United States) Vol. 42:25; ISSN LIFSA
• Country of Publication: United States
• Language: English

Related Subjects

550201* -- Biochemistry-- Tracer Techniques
59 BASIC BIOLOGICAL SCIENCES
ANIMALS
ANTIMETABOLITES
AUTONOMIC NERVOUS SYSTEM AGENTS
AUTORADIOGRAPHY
BIOCHEMICAL REACTION KINETICS
BODY
BRAIN
CENTRAL NERVOUS SYSTEM
DRUGS
ENDORPHINS
KINETICS
LABELLED COMPOUNDS
MAMMALS
MEMBRANE PROTEINS
NERVOUS SYSTEM
NEUROREGULATORS
ORGANIC COMPOUNDS
ORGANS
PROTEINS
RATS
REACTION KINETICS
RECEPTORS
RODENTS
TRITIUM COMPOUNDS
VERTEBRATES