Electrical stimulation of the substantia nigra and changes of 2-phenylethylamine synthesis in the rat striatum.
In rats pretreated with deprenyl (2 mg/kg), electrical stimulation of the left substantia nigra produced an increase in the concentrations of 3,4-dihydroxyphenylacetic acid and homovanillic acid in the left striatum by 57 and 45%, but the levels of 2-phenylethylamine and p-tyramine decreased by 22 and 41%, respectively, as compared with those in the right striatum. The administration of alpha-methyl-p-tyrosine (1.25 mg/kg, i.p.), a tyrosine hydroxylase inhibitor, 1 h before nigral stimulation, did not affect the concentration of 2-phenylethylamine in unstimulated striata but prevented the stimulation-induced decrease in the concentration of 2-phenylethylamine. Neither stimulation nor alpha-methyl-p-tyrosine affected the activity of monoamine oxidase A or B, and stimulation did not produce any change in striatal blood flow, a finding demonstrating that the changes in the rate of accumulation of 2-phenylethylamine were not due to changes in catabolism or removal of 2-phenylethylamine from the brain. These experiments demonstrate that the rate of synthesis of striatal 2-phenylethylamine is decreased following nigral stimulation and that this effect is blocked after partial inhibition of tyrosine hydroxylase. This suggests that 2-phenylethylamine is present in tyrosine hydroxylase-containing neurons and therefore supports the coexistence of 2-phenylethylamine and dopamine in the nigrostriatal pathway.
Juorio
A V
AV
Neuropsychiatric Research Unit, University of Saskatchewan, Saskatoon, Canada.
Paterson
I A
IA
Zhu
M Y
MY
Matte
G
G
D015102:3,4-Dihydroxyphenylacetic Acid / Q000378:metabolism; D000818:Animals; D003342:Corpus Striatum / Q000187:drug effects / Q000378:metabolism*; D004558:Electric Stimulation; D006719:Homovanillic Acid / Q000378:metabolism; D007700:Kinetics; D008297:Male; D008781:Methyltyrosines / Q000494:pharmacology; D008995:Monoamine Oxidase / Q000378:metabolism; D010627:Phenethylamines / Q000378:metabolism*; D051381:Rats; D011919:Rats, Inbred Strains; D013378:Substantia Nigra / Q000502:physiology*; D014439:Tyramine / Q000378:metabolism; D014446:Tyrosine 3-Monooxygenase / Q000037:antagonists & inhibitors; D019805:alpha-Methyltyrosine
D008781:Methyltyrosines; D010627:Phenethylamines; D015102:3,4-Dihydroxyphenylacetic Acid; C029261:phenethylamine; D019805:alpha-Methyltyrosine; D014446:Tyrosine 3-Monooxygenase; D008995:Monoamine Oxidase; D006719:Homovanillic Acid; D014439:Tyramine