title: Failure of FK506 (tacrolimus) to alleviate apomorphine-induced circling in rat Parkinson model in spite of some cytoprotective effects in SH-SY5Y dopaminergic cells.
abstract: The mechanism of action of the neurotoxin 6-hydroxydopamine (6-OHDA) is thought to involve the generation of free radicals and subsequent apoptotic processes. We have demonstrated in vitro that the neuroimmunophilin, FK506 (10-100 nM), dose dependently and significantly restored the ROS production to the control level, increased the Bcl-2 protein level, partly inhibited the cytochrome C release from mitochondria and reduced the caspase-3 activation in SH-SY5Y cells. On the other hand, there was no significant restoration of the ATP level by FK506 and the toxin activated proteins, p53 and Bax, were not normalized by FK506. In support of these latter results, daily administration of FK506 for 7 days to rats (0.5, 1 and 3 mg/kg i.p.) did not significantly prevent the apomorphine-induced contralateral circling, measured 2 weeks after unilateral nigral lesioning. Moreover, FK506 pretreatment did not significantly lower the toxin elevated lipid peroxidation levels, indicating that oxidative stress was present even after the FK506 treatment in the lesioned striatum. Taken together, our results with FK506 are inconsistent. We confirm the antioxidant nature of FK506, that is, it blocks ROS production in SH-SY5Y cells. However, there were no significant protective effects in any apoptotic analyses in SH-SY5Y cells and in animal studies, a 7-day FK506 pre-treatment was not able to reverse the toxic effect of 6-OHDA in a rat model of Parkinson's disease.
authors.affiliation: Department of Pharmacology and Toxicology, University of Kuopio, Harjulantie 1A, P.O. Box 1627, FIN-70211 Kuopio, Finland. manakova@uku.fi
authors.forename: Sárka
authors.initials: S
authors.lastname: Manáková
authors.forename: Amanpreet
authors.initials: A
authors.lastname: Singh
authors.forename: Tiina
authors.initials: T
authors.lastname: Kääriäinen
authors.forename: Heli
authors.initials: H
authors.lastname: Taari
authors.forename: Shrinivas K
authors.initials: SK
authors.lastname: Kulkarni
authors.forename: Pekka T
authors.initials: PT
authors.lastname: Männistö
mesh_terms: D000818:Animals; D001058:Apomorphine / Q000494:pharmacology; D001522:Behavior, Animal / Q000187:drug effects; D053148:Caspase 3; D020169:Caspases / Q000187:drug effects; D016923:Cell Death / Q000187:drug effects; D045744:Cell Line, Tumor; D004195:Disease Models, Animal; D004298:Dopamine / Q000378:metabolism*; D018491:Dopamine Agonists / Q000494:pharmacology; D004305:Dose-Response Relationship, Drug; D020104:Immunophilins; D008297:Male; D009043:Motor Activity / Q000187:drug effects; D009410:Nerve Degeneration / Q000139:chemically induced; D009447:Neuroblastoma; D009474:Neurons / Q000187:drug effects / Q000378:metabolism*; D018696:Neuroprotective Agents / Q000494:pharmacology*; D016627:Oxidopamine; D010300:Parkinson Disease / Q000188:drug therapy* / Q000503:physiopathology*; D011897:Random Allocation; D051381:Rats; D017208:Rats, Wistar; D016559:Tacrolimus / Q000494:pharmacology*
chemical_list: D018491:Dopamine Agonists; D018696:Neuroprotective Agents; D016627:Oxidopamine; C505410:Casp3 protein, rat; D053148:Caspase 3; D020169:Caspases; D020104:Immunophilins; D001058:Apomorphine; D004298:Dopamine; D016559:Tacrolimus