N. Hashimoto et al., DOPAMINE HAS INHIBITORY AND ACCELERATING EFFECTS ON ISCHEMIA-INDUCED NEURONAL CELL-DAMAGE IN THE RAT STRIATUM, Brain research bulletin, 33(3), 1994, pp. 281-288
Dopaminergic (DAergic) influence on ischemic neuronal cell damage in t
he dorsolateral striatum was studied. Intact and 6-hydroxydopamine (6-
OHDA) lesioned rats, with and without pretreatment by D1 and D2 DA ant
agonists, were subjected to 20 min forebrain ischemia. Extracellular D
A and glutamate (Glu) were measured using microdialysis technique. His
tological examination was performed on the dorsolateral striatum and t
he hippocampal CA1 area 24 h after ischemia. DA increased 400-500 time
s the control level during ischemia among the groups except the 6-OHDA
lesioned group. No significant changes were observed in the concentra
tion of 3,4-dihydroxyphenylacetic acid (DOPAC), but a transient decrea
se was seen in homovanillic acid (HVA). Due to ischemia, Glu increased
up to about 5 times the control level among the groups. Neuronal dama
ge in the dorsolateral striatum was slightly attenuated by 6-OHDA lesi
on. Treatment by spiperone (D2 antagonist, 7 mug/kg IP) alone attenuat
ed the damage strongly. Treatment by SCH23390 (D1 antagonist, 2.5 mg/k
g IP) alone or both D1 and D2 antagonists had no effects. Data suggest
that excessive Glu and DA are involved in neuronal cell damage. DA mi
ght enhance the damage via D2 but inhibit via D1 receptor.