Treatment with 6-hydroxydopamine in planaria (Dugesia gonocephala s.l.): morphological and behavioral study.
Morpho-functional and behavioral effects of exposure to 6-hydroxydopamine (OHDA)-HCI (24 microg/ml per day for 24 h and 7 days) were studied in planarias (Dugesia gonocephala s.l.). Exposure to 6-OHDA-HC1 for 24 h produced hypokinesia of the specimens. These behavioral changes were more pronounced, leading to complete immobility, after 7 days of exposure to the neurotoxin. Moreover, specimens exposed to 6-OHDA-HCI for 24 h and 7 days failed to show any behavioral response to nomifensine, thus furnishing evidence of the damage of presynaptic dopamine terminals. Exposure to 6-OHDA-HCl for 24 h significantly reduced cathecolamine content in neuropil region, as demonstrated by histochemistry, and electron-dense presynaptic vesicles, as observed on electron microscopy examination. All these alterations were significantly more pronounced and were accompanied by swelling and strong increase of electron-density in cytoplasm of numerous neurons after exposure to the neurotoxin for 7 days. This appears to be the first demonstration of the neurotoxic effects of 6-OHDA-HCI in flatworms.
Caronti
B
B
Dipartimento di Scienze Neurologiche, Università La Sapienza, Viale dell'Università, Rome, Italy.
Margotta
V
V
Merante
A
A
Pontieri
F E
FE
Palladini
G
G
D000818:Animals; D001522:Behavior, Animal / Q000187:drug effects*; D002395:Catecholamines / Q000032:analysis; D018765:Dopamine Uptake Inhibitors / Q000627:therapeutic use; D018476:Hypokinesia / Q000139:chemically induced* / Q000188:drug therapy; D009043:Motor Activity / Q000187:drug effects / Q000502:physiology; D019581:Neuropil / Q000737:chemistry / Q000187:drug effects; D009627:Nomifensine / Q000627:therapeutic use; D009899:Optic Lobe, Nonmammalian / Q000187:drug effects* / Q000473:pathology / Q000502:physiology; D016627:Oxidopamine / Q000633:toxicity*; D010932:Planarians / Q000166:cytology / Q000187:drug effects*; D013565:Sympatholytics / Q000633:toxicity*; D013572:Synaptic Vesicles / Q000187:drug effects / Q000648:ultrastructure
D002395:Catecholamines; D018765:Dopamine Uptake Inhibitors; D013565:Sympatholytics; D009627:Nomifensine; D016627:Oxidopamine