Alcohol-, nicotine-, and cocaine-evoked release of morphine from invertebrate ganglia: model system for screening drugs of abuse
Zhu W, Mantione KJ, Casares FM, Cadet P, Kim JW, Bilfinger TV,
Kream RM, Khalill S, Singh S, Stefano GB.
Neuroscience Research Institute,
State University of New York - College at Old Westbury,
Old Westbury, NY 11568, USA.
Med Sci Monit. 2006 May;12(5):BR155-61.


BACKGROUND: Invertebrates express regulatory receptors, transporters, and channels responsive to established drugs of abuse, many of which mediate their effects through catecholamine pathways. We hypothesized that invertebrate neural systems may serve as models by which to evaluate the interactive pharmacological effects of these agents. MATERIAL AND METHODS: Ex vivo pharmacological trials determined the effects of saturating levels of ethanol on morphine levels in pooled Mytilus edulis ganglia via HPLC coupled to electrochemical detection and/or HPLC/RIA analyses. Additional trials evaluated the ability of ethanol, nicotine, and cocaine, to promote evoked release of 125I-labeled morphine from neural tissues, because intrinsically low levels of morphine did not allow direct quantification of its release. RESULTS: Incubation of pooled M. edulis pedal ganglia with 200 mM ethanol (approximately 1% ethanol v/v) resulted in a two-fold increase in morphine concentration at 15 min, return to baseline at 30 min, and a 50% decrease in morphine concentration at 60 min. Separate incubations of pooled M. edulis pedal ganglia and H. americanus nerve cord with ethanol, cocaine, and nicotine resulted in a statistically significant enhancement of 125I-trace labeled morphine release. CONCLUSIONS:The stimulatory effects of ethanol, nicotine, and cocaine on cellular expression and release of endogenous morphine suggest convergent mechanisms underlying the reinforcing and addictive properties for a variety of drugs of abuse. The evolutionary conservation of L-tyrosine as a common precursor to catecholamine and opiate/opioid signaling systems may define a functional triad involving endogenous morphine, dopamine, and other classes of addictive drugs.
Zero tolerance?
Wilhelm Sertürner
Kadian v MS Contin
Morphine: structure
High dose morphine
Morphine plus Viagra
Endogenous morphine
Micro-opioid receptors
Morphine and serotonin
Morphine and magnesium
Is morphine a smart drug?
Opioids, mood and cognition
Is morphine an antidepressant?
Methadone, morphine and heroin
Morphine, pain and beta-endorphin
Tolerance, sensitization and dependence
Morphine as a neurotransmitter/neuromodulator
Endogenous morphine made by human neuroblastoma cells
Endogenous morphine has signaling functions in Purkinje cells

morphine swan
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Future Opioids
BLTC Research
Utopian Surgery?
The Abolitionist Project
The Hedonistic Imperative
The Reproductive Revolution
Critique of Huxley's Brave New World

The Good Drug Guide
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The Responsible Parent's Guide
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