HOMEPRODUCTSCOMPANYCONTACTFAQResearchDictionaryPharmaSign Up FREE or Login

Up-regulation of adenosine transporter-binding sites in striatum and hypothalamus of opiate tolerant mice.

Abstract
Opioid-adenosine interactions have been demonstrated at both cellular and behavioral levels. Short-term morphine treatment has been shown to enhance adenosine release in brain and spinal tissues. Since adenosine uptake and release is regulated by a nitrobenzylthioinosine-sensitive adenosine transporter, we examined the effects of morphine treatment on this transporter-binding site. Adenosine transporter-binding sites were examined using equilibrium binding studies with [3H]nitrobenzylthioinosine in brain regions of morphine-treated mice. A 72-hour morphine pellet implantation procedure, which previously produced up-regulation of central adenosine A1 receptors and created a state of opiate dependence [G.B. Kaplan, K.A. Leite-Morris and M.T. Sears, Alterations in adenosine A receptors in morphine dependence, Brain Res., 657 (1994) 347-350], was used in this current study. This chronic morphine treatment significantly increased adenosine transporter-binding site concentrations in striatum and hypothalamus by 12 and 37%, respectively, compared to vehicle pellet implantation. No effects of morphine treatment were demonstrated in cortex, hippocampus, brainstem or cerebellum. In behavioral studies, mice receiving this same chronic morphine or vehicle treatment were given saline or morphine injections (40 or 50 mg/kg i.p.) followed by ambulatory activity monitoring. In the chronic vehicle treatment group, morphine injections significantly stimulated ambulatory activity while in the chronic morphine treatment group there was no such stimulation by acute morphine, suggestive of opiate tolerance. Morphine-induced up-regulation of striatal and hypothalamic adenosine transporter sites could potentially alter extracellular adenosine release and adenosine receptor activation and mediate aspects of opiate tolerance and dependence.
AuthorsG B Kaplan, K A Leite-Morris
JournalBrain research (Brain Res) Vol. 763 Issue 2 Pg. 215-20 (Jul 25 1997) ISSN: 0006-8993 [Print] Netherlands
PMID9296562 (Publication Type: Journal Article, Research Support, Non-U.S. Gov't)
Chemical References
  • Carrier Proteins
  • Membrane Proteins
  • Narcotics
  • Nucleoside Transport Proteins
  • Morphine
  • Adenosine
Topics
  • Adenosine (metabolism)
  • Animals
  • Binding Sites (drug effects, physiology)
  • Brain Stem (chemistry, metabolism)
  • Carrier Proteins (metabolism)
  • Cerebellum (chemistry, metabolism)
  • Corpus Striatum (chemistry, metabolism)
  • Drug Tolerance
  • Hypothalamus (chemistry, metabolism)
  • Male
  • Membrane Proteins (metabolism)
  • Mice
  • Mice, Inbred Strains
  • Morphine (pharmacology)
  • Narcotics (pharmacology)
  • Nucleoside Transport Proteins
  • Up-Regulation (drug effects)

Join CureHunter, for free Research Interface BASIC access!

Take advantage of free CureHunter research engine access to explore the best drug and treatment options for any disease. Find out why thousands of doctors, pharma researchers and patient activists around the world use CureHunter every day.
Realize the full power of the drug-disease research graph!


Choose Username:
Email:
Password:
Verify Password:
Enter Code Shown: