Comparative behavioral, biochemical and pigmentary effects of MPTP, MPP+ and paraquat in Rana pipiens.
We demonstrate that injections of 1-methyl-4-phenyl-1,2,3,6-tetra-hydropyridine (MPTP), 1-methyl-4-phenyl-pyridinium ion (MPP+) and Paraquat (PQ+) produce in Rana Pipiens different behavioral, biochemical and skin pigmentation changes. MPTP causes in frogs the main symptoms of Parkinsonism (rigidity, akinesia and tremor) and it darkens the skin of animals. It also decreases brain and, less so, adrenal medulla dopamine. These effects are blocked by Pargyline. MPP+ causes the same symptoms but more rapidly. In contrast, skin pigmentation is clearly lightened. Brain and particularly adrenal dopamine reserves are nearly abolished. Pargyline increases these effects. Paraquat, in a cumulative fashion, eventually causes the same behavioral changes and a slight increase in pigmentation. It initially produces an increase in brain and adrenal dopamine concentrations, but later a significant dopamine concentration decrease. Pargyline potentiates these long term effects, blocks the dopamine increase, but reverses the PQ+ effect upon melanin, producing the same depigmentation as MPP+ alone.
D015632:1-Methyl-4-phenyl-1,2,3,6-tetrahydropyridine; D015655:1-Methyl-4-phenylpyridinium; D000313:Adrenal Medulla / Q000032:analysis / Q000187:drug effects; D000818:Animals; D001522:Behavior, Animal / Q000187:drug effects*; D001923:Brain Chemistry / Q000187:drug effects; D004298:Dopamine / Q000032:analysis; D004347:Drug Interactions; D004837:Epinephrine / Q000032:analysis; D008547:Melanophores / Q000032:analysis / Q000187:drug effects; D009043:Motor Activity / Q000187:drug effects; D009638:Norepinephrine / Q000032:analysis; D010269:Paraquat / Q000633:toxicity*; D010293:Pargyline / Q000494:pharmacology; D010302:Parkinson Disease, Secondary / Q000139:chemically induced; D010858:Pigmentation / Q000187:drug effects*; D011187:Posture; D011725:Pyridines / Q000633:toxicity*; D011726:Pyridinium Compounds / Q000633:toxicity*; D011894:Rana pipiens; D012018:Reflex / Q000187:drug effects
D011725:Pyridines; D011726:Pyridinium Compounds; D010293:Pargyline; D015632:1-Methyl-4-phenyl-1,2,3,6-tetrahydropyridine; D010269:Paraquat; D015655:1-Methyl-4-phenylpyridinium; D004298:Dopamine; D009638:Norepinephrine; D004837:Epinephrine