Antagonistic effects of beta-phenylethylamine on quinpirole- and (-)-sulpiride-induced changes in evoked dopamine release from rat striatal slices.
To assess the role of beta-phenylethylamine in aspects of dopamine release, we measured the level of beta-phenylethylamine in the rat striatum after killing the rats by microwave irradiation. We then investigated the effect of beta-phenylethylamine on electrically evoked dopamine release from rat striatal slices in vitro. The striatal beta-phenylethylamine level was 46.5 +/- 3.5 ng/g wet tissue, equivalent to 0.3 micromol/l. Superfusion with low concentrations of beta-phenylethylamine up to 1 micromol/l had no effect on spontaneous or electrically evoked dopamine release from striatal slices. Quinpirole reduced the evoked dopamine release from slices in a concentration-dependent manner. The quinpirole-induced reduction of evoked dopamine release was attenuated 30% by superfusion with 0.3 micromol/l beta-phenylethylamine. Moreover, the (-)-sulpiride (0.1 micromol/l)-induced increase in evoked dopamine release was also attenuated by superfusion with 0.3 micromol/l beta-phenylethylamine. These data indicate that submicromolar levels of beta-phenylethylamine could modify the dopamine autoreceptor mediated changes in evoked dopamine release from rat striatal slices.
Yamada
S
S
Institute of Brain Diseases, School of Medicine, Kurume University, Fukuoka, Japan. s-yamada@kurume.ktarn.or.jp
Harano
M
M
Tanaka
M
M
D000818:Animals; D003342:Corpus Striatum / Q000187:drug effects* / Q000378:metabolism; D004298:Dopamine / Q000378:metabolism*; D018491:Dopamine Agonists / Q000494:pharmacology; D018492:Dopamine Antagonists / Q000494:pharmacology; D066298:In Vitro Techniques; D008297:Male; D010627:Phenethylamines / Q000494:pharmacology*; D011619:Psychotropic Drugs / Q000494:pharmacology; D019257:Quinpirole / Q000037:antagonists & inhibitors*; D051381:Rats; D017208:Rats, Wistar; D013469:Sulpiride / Q000037:antagonists & inhibitors*
D018491:Dopamine Agonists; D018492:Dopamine Antagonists; D010627:Phenethylamines; D011619:Psychotropic Drugs; D019257:Quinpirole; C029261:phenethylamine; D013469:Sulpiride; D004298:Dopamine