Brain receptors for thyrotropin releasing hormone in morphine tolerant-dependent rats

Conference · Fri Feb 28 23:00:00 EST 1986 · Fed. Proc., Fed. Am. Soc. Exp. Biol.; (United States)

OSTI ID:5321777

Bhargava, H N; Das, S

The effect of chronic treatment of rats with morphine and its subsequent withdrawal on the brain receptors for thyrotropin releasing hormone (TRH) labeled with /sup 3/H-(3MeHis/sup 2/)TRH (MeTRH). Male Sprague Dawley rats were implanted with 4 morphine pellets (each containing 75 mg morphine base) during a 3-day period. Placebo pellet implanted rats served as controls. Both tolerance to and dependence on morphine developed as a result of this procedure. For characterization of brain TRH receptors, the animals were sacrificed 72 h after the implantation of first pellet. In another set of animals the pellets were removed and were sacrificed 24 h later. The binding of /sup 3/H-MeTRH to membranes prepared from brain without the cerebellum was determined. /sup 3/H-MeTRH bound to brain membranes prepared from placebo pellet implanted rats at a single high affinity site with a B/sub max/ value of 33.50 +/- 0.97 fmol/mg protein and a K/sub d/ of 5.18 +/- 0.21 nM. Implantation of morphine pellets did not alter the B/sub max/ value of /sup 3/H-MeTRH but decreased the K/sub d/ value significantly. Abrupt or naloxone precipitated withdrawal of morphine did not alter B/sub max/ or the K/sub d/ values. The binding of /sup 3/H-MeTRH to brain areas was also determined. The results suggest that the development of tolerance to morphine is associated with enhanced sensitivity of brain TRH receptors, however abrupt withdrawal of morphine does not change the characteristics of brain TRH receptors.

• Research Organization: Univ. of Illinois, Chicago
• OSTI ID: 5321777
• Report Number(s): CONF-8604222-
• Journal Information: Fed. Proc., Fed. Am. Soc. Exp. Biol.; (United States), Journal Name: Fed. Proc., Fed. Am. Soc. Exp. Biol.; (United States) Vol. 45:3; ISSN FEPRA
• Country of Publication: United States
• Language: English

Related Subjects

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560305* -- Chemicals Metabolism & Toxicology-- Vertebrates-- (-1987)
59 BASIC BIOLOGICAL SCIENCES
63 RADIATION, THERMAL, AND OTHER ENVIRON. POLLUTANT EFFECTS ON LIVING ORGS. AND BIOL. MAT.
AFFINITY
ALKALOIDS
ANALGESICS
ANIMALS
BIOCHEMICAL REACTION KINETICS
BODY
BRAIN
CELL CONSTITUENTS
CELL MEMBRANES
CENTRAL NERVOUS SYSTEM
CENTRAL NERVOUS SYSTEM DEPRESSANTS
CHRONIC EXPOSURE
DRUGS
HORMONES
IMPLANTS
ISOTOPE APPLICATIONS
KINETICS
LABELLED COMPOUNDS
MAMMALS
MEMBRANE PROTEINS
MEMBRANES
MORPHINE
NARCOTICS
NERVOUS SYSTEM
OPIUM
ORGANIC COMPOUNDS
ORGANS
PROTEINS
RATS
REACTION KINETICS
RECEPTORS
RODENTS
SENSITIVITY
TOLERANCE
TRACER TECHNIQUES
TRITIUM COMPOUNDS
VERTEBRATES