2-phenylethylamine and methamphetamine enhance the spinal monosynaptic reflex by releasing noradrenaline from the terminals of descending fibers.
Experiments were performed on spinalized rats transected at C1. Intravenous administration of 2-phenylethylamine-HCl (PEA-HCl) (0.3 and 1 mg/kg, i.v.) and methamphetamine-HCl (MAP-HCl) (0.1 and 0.3 mg/kg, i.v.) increased the amplitude of the monosynaptic reflex (MSR). The increase of the MSR caused by PEA and MAP was antagonized by prazosin-HCl and abolished by the pretreatment with reserpine (i.p.) and 6-hydroxydopamine (intracisternally, 14 days previously). A dopamine D1 antagonist, SK&F 83566-HBr (0.01 mg/kg, i.v.), and a D2 antagonist. YM-09151-2 (0.3 mg/kg, i.v.), did not antagonize the increasing effects produced by PEA and MAP. An inhibitor of type-B monoamine oxidase, (-)deprenyl-HCl (1 mg/kg, i.v.), prolonged the effect of PEA but not that of MAP, suggesting that PEA alone, and not its metabolites, enhanced the MSR. These results suggest that PEA and MAP increase the amplitude of the MSR by releasing noradrenaline from the terminals of descending noradrenergic fibers, and that PEA, an endogenous trace amine, has a mechanism of action similar to that of MAP.
Ono
H
H
Department of Toxicology and Pharmacology, Faculty of Pharmaceutical Sciences, University of Tokyo, Japan.
Ito
H
H
Fukuda
H
H
D015647:2,3,4,5-Tetrahydro-7,8-dihydroxy-1-phenyl-1H-3-benzazepine / Q000031:analogs & derivatives / Q000494:pharmacology; D000818:Animals; D001794:Blood Pressure / Q000187:drug effects; D006892:Hydroxydopamines / Q000494:pharmacology; D008297:Male; D008694:Methamphetamine / Q000494:pharmacology*; D008996:Monoamine Oxidase Inhibitors / Q000494:pharmacology; D009411:Nerve Endings / Q000187:drug effects / Q000378:metabolism*; D009474:Neurons / Q000187:drug effects / Q000378:metabolism*; D009638:Norepinephrine / Q000378:metabolism*; D016627:Oxidopamine; D010627:Phenethylamines / Q000494:pharmacology*; D011224:Prazosin / Q000494:pharmacology; D011619:Psychotropic Drugs / Q000494:pharmacology*; D051381:Rats; D011919:Rats, Inbred Strains; D011954:Receptors, Dopamine / Q000187:drug effects / Q000502:physiology; D017447:Receptors, Dopamine D1; D017448:Receptors, Dopamine D2; D012023:Reflex, Monosynaptic / Q000187:drug effects*; D012110:Reserpine / Q000494:pharmacology; D013116:Spinal Cord / Q000166:cytology / Q000187:drug effects
D015647:2,3,4,5-Tetrahydro-7,8-dihydroxy-1-phenyl-1H-3-benzazepine; D006892:Hydroxydopamines; D008694:Methamphetamine; D008996:Monoamine Oxidase Inhibitors; D009638:Norepinephrine; D016627:Oxidopamine; D010627:Phenethylamines; D011224:Prazosin; D011619:Psychotropic Drugs; D011954:Receptors, Dopamine; D017447:Receptors, Dopamine D1; D017448:Receptors, Dopamine D2; D012110:Reserpine; C029261:phenethylamine; C044846:SKF83566