Tagma-specific distribution of FXPRLamides in the nervous system of the American cockroach

FXPRLamide (pyrokinin) distribution in the central nervous system and major neurohaemal organs of the American cockroach and related cockroach species was investigated using immunocytochemistry and MALDI-TOF mass spectrometry . Six isoforms (Pea-PK-1 through -6) were found in different neurohaemal re lease sites. Pea-PK-1-4 and Pea-PK-6 are all stored in the retrocerebral co mplex and are all produced in cells located in both the suboesophageal gang lion (SOG) and the tritocerebrum. These pyrokinins were found to be concent rated in and around the corpora allata. No other known peptides were detect able in such high concentrations in this neurohaemal organ. They reach the corpora cardiaca/allata via the nervi corporis cardiaci-1 (NCC-1), NCC-3, a nd nervi corporis allati-2 (NCA-2). Abdominal perisympathetic organs contai ned only Pea-PK-5 and low quantities of the sequence-related Pea-PK-6. Neit her Pea-PK-5 nor-PK-6 was detected in thoracic perisympathetic organs. It i s likely that the expression of pyrokinins in the central nervous system is tagma (body region)-specific. Pea-PK-6 was identified during this study as follows: Ser-Glu-Ser-Glu-Val-Pro-Gly-Met-Trp-Phe-Gly-Pro-Arg-Leu-NH2. J. C omp. Neurol. 419:352-363, 2000. (C) 2000 Wiley-Liss, Inc.