Abstract
To extend our earlier data on synergistic action of tetrahydroisoquinolines and morphine, we have investigated the analgesic effects of 1,2,3,4-tetrahydroisoquinoline (TIQ) and its 1-methyl-(1-MeTIQ) and N-methyl (N-MeTIQ) analogs on analgesia induced by morphine and oxotremorine. 1-MeTIQ and N-MeTIQ induced a moderate, delayed and prolonged analgesic action measured in the tail-flick test in CD-1 mice; 1-MeTIQ and TIQ prolonged the opiate (morphine, 2.5 mg/kg i.p.) analgesia while TIQ and N-TIQ potentiated cholinergic (oxotremorine, 0.02 mg/kg i.p.) analgesia. The involvement of the opioid and noradrenergic systems in this effect is discussed.
MeSH terms
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Acetylcholine / metabolism
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Analgesics / pharmacology*
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Animals
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Central Nervous System / drug effects
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Central Nervous System / metabolism
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Central Nervous System / physiopathology
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Drug Synergism
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Male
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Mice
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Morphine / pharmacology*
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Nociceptors / drug effects
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Nociceptors / physiology
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Norepinephrine / metabolism
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Opioid Peptides / metabolism
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Oxotremorine / pharmacology*
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Pain / drug therapy*
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Pain / metabolism
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Pain / physiopathology
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Pain Measurement / drug effects
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Reaction Time / drug effects
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Reaction Time / physiology
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Receptors, Adrenergic, alpha-2 / drug effects
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Receptors, Adrenergic, alpha-2 / metabolism
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Receptors, Opioid / drug effects
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Receptors, Opioid / metabolism
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Tetrahydroisoquinolines / pharmacology*
Substances
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Analgesics
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Opioid Peptides
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Receptors, Adrenergic, alpha-2
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Receptors, Opioid
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Tetrahydroisoquinolines
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1-methyl-1,2,3,4-tetrahydroisoquinoline
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1,2,3,4-tetrahydroisoquinoline
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Oxotremorine
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Morphine
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Acetylcholine
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Norepinephrine