Synergistic sedative effect of selective MAO-A, but not MAO-B, inhibitors and melatonin in frogs
Total suppression of righting reflex in frogs (Rana pipiens, 25–35 mg b.w.) was observed after combined administration of melatonin (12.5 mg/kg) and selective inhibitors of MAO-A: clorgyline (2.5 mg/kg) and moclobemide (50 mg/kg) but not MAO-B: selegiline (25 mg/kg) and Ro-19-6327 (50 mg/kg). None of these drugs alone affected the righting reflex. Clorgyline and selegiline selectively inhibited brain MAO-A and MAO-B activity (by more than 90%), resp. Frogs might represent a convenient model to study the selective MAO-A and B type inhibitors since they provide the opportunity to correlate behaviour and biochemical changes induced by MAO inhibitors.
KeywordsRana Pipiens Pineal Melatonin Melatonin Suppression Melatonin Injection Melatonin Biosynthesis
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