Selective depletion of dopamine, octopamine, and 5-hydroxytryptamine in the nervous tissue of the cockroach (Periplaneta americana)

J Neurochem. 1988 Aug;51(2):535-41. doi: 10.1111/j.1471-4159.1988.tb01071.x.


High-performance liquid chromatography with electrochemical detection was used to measure the concentrations of 3,4-dihydroxyphenylethylamine (dopamine), 5-hydroxytryptamine (5-HT), p-hydroxyphenylethanolamine (octopamine), alpha-methyl-p-tyrosine, and tryptophan in the cerebral ganglia of cockroaches (Periplaneta americana) after peripheral administration of alpha-methyl-p-tyrosine and alpha-methyltryptophan. In addition, the levels of dopamine, 5-HT, octopamine, alpha-methyl-p-tyrosine, and tryptophan were determined after injection of alpha-methyl-p-tyrosine, 6-hydroxydopamine, or 5,7-dihydroxytryptamine directly into the cerebral ganglia by means of microinjection needles. Peripheral administration of alpha-methyl-p-tyrosine (400-1,600 micrograms/insect) caused a reduction in dopamine and 5-HT concentrations in cockroach cerebral ganglia, although the reduction in dopamine concentrations was more pronounced. Peripheral injections of alpha-methyl-p-tyrosine also reduced octopamine levels in the cerebral ganglia. Peripheral injection of alpha-methyltryptophan (400-1,600 micrograms/insect) caused a marked reduction in 5-HT and tryptophan concentrations in cockroach cerebral ganglia without altering dopamine or octopamine concentrations. Central injections of alpha-methyl-p-tyrosine (80 micrograms/insect) reduced dopamine concentrations in the cerebral ganglia. However, neither 6-hydroxydopamine (20 micrograms/insect) nor 5,7-dihydroxytryptamine (20 micrograms/insect) caused reductions in amine levels when applied near or directly into the cerebral ganglia. The results suggest that specific lesions of aminergic neurons in insects by either 6-hydroxydopamine or 5,7-dihydroxytryptamine are impractical. The specific, long-lasting depletion of 5-HT by alpha-methyltryptophan suggests that this chemical may be useful in elucidating the functions of 5-HT in insects.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • 5,7-Dihydroxytryptamine / metabolism
  • Animals
  • Cockroaches / metabolism*
  • Dopamine / metabolism*
  • Male
  • Methyltyrosines / metabolism
  • Nervous System / metabolism*
  • Octopamine / metabolism*
  • Periplaneta / metabolism*
  • Reference Values
  • Serotonin / metabolism*
  • Tryptophan / metabolism
  • alpha-Methyltyrosine


  • Methyltyrosines
  • Octopamine
  • 5,7-Dihydroxytryptamine
  • Serotonin
  • alpha-Methyltyrosine
  • Tryptophan
  • 2-octopamine
  • Dopamine