Neuropharmacology and Neurotoxiology: PDF OnlyMännistö Pekka T.; Tuomainen, Päivi; Borisenko, Sergey A.; Tuominen, Raimo K.NeuroReport: July 1992 - p 641-644 Buy Abstract A new COMT inhibitor, nitecapone (OR-462) or clorgyline, a MAO-A inhibitor, was infused into the 3rd brain ventricle (i.c.v.) of conscious male rats. None of the enzyme inhibitors given alone alter hypothalamic or striatallevels of L-dopa, dopamine or their metabolites. Most of the rats were pretreated with levodopa/carbidopa (LD/CD, 15/30 mg kg-1 intraperitoneally). Now, the action of nitecapone is localized in the hypothalamus since homovanillic acid (HVA) is decreased there, not in the striatum. The levels of 3-o-methyldopa (3-OMD) are not changed in either brain region, suggesting a lack of the peripheral leakage of nitecapone. Clorgyline (3 and 10 $mUg rat-1) elevates hypothalamic and dopamine levels. Nitecapone and cloryline decrease prolactin (PRL) levels below those reduced by LD/CD treatment. © Lippincott-Raven Publishers.