Depletion of striatal beta-phenylethylamine following dopamine but not 5-HT denervation.
The effects of lesions of the substantia nigra (electrolytic 2 mA 10 sec, or 6-OHDA 2 or 8 micrograms) and of the midbrain raphé nuclei (electrolytic 2 X 1.0 mA 10 sec) at 7 days postlesion on striatal levels of beta-phenylethylamine, DA, DOPAC, HVA, 5-HT and 5-HIAA and on hypothalamic levels of beta-phenylethylamine, DA, NA, 5-HT and 5-HIAA were investigated. In the presence of deprenyl (2 mg kg-1 2 hr SC), both electrolytic and 6-OHDA-induced dopamine-depleting lesions of the nigra but not 5-HT-depleting lesions of the raphé nuclei resulted in a marked decrease in the accumulation of beta-phenylethylamine. The marked reduction in accumulation of striatal beta-phenylethylamine in response to lesions of the substantia nigra indicates that the intraneuronal compartment is a major site of striatal beta-phenylethylamine synthesis. An equivalent decrease (approximately 40%) in the accumulation of 5-HT was observed following electrolytic lesions of the substantia nigra or raphé nuclei after administration of L-5-HTP (200 mg kg-1 hr IP). As L-5-HTP at the dose employed in this study is taken up non-selectively by both DA- and 5-HT-containing neurones the loss of L-AAD following nigral and raphé lesions was apparently equivalent. These results indicate that depletion of beta-phenylethylamine may not be simply attributable to a general loss of L-AAD following lesions of monoamine-containing neurones and suggest either co-localisation of beta-phenylethylamine and DA or the existence of distinct beta-phenylethylamine-containing neurones.
D000818:Animals; D001679:Biogenic Amines / Q000378:metabolism*; D003342:Corpus Striatum / Q000378:metabolism*; D003714:Denervation; D004298:Dopamine / Q000378:metabolism; D006892:Hydroxydopamines / Q000494:pharmacology; D007031:Hypothalamus / Q000378:metabolism*; D008297:Male; D016627:Oxidopamine; D010627:Phenethylamines / Q000378:metabolism*; D011903:Raphe Nuclei / Q000502:physiology*; D051381:Rats; D011919:Rats, Inbred Strains; D012642:Selegiline / Q000494:pharmacology; D012701:Serotonin / Q000378:metabolism; D013378:Substantia Nigra / Q000502:physiology*
D001679:Biogenic Amines; D006892:Hydroxydopamines; D010627:Phenethylamines; D012642:Selegiline; C029261:phenethylamine; D012701:Serotonin; D016627:Oxidopamine; D004298:Dopamine