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Biogenic amines in Nematoda have previously been found by means of high-performance liquid chromatography (HPLC) equipped with various detectors. The methods of sample preparation have differed widely. In this study, we tested the influence of experimental conditions (temperature and duration of exposure to light, centrifugation or individual recovery by pipetting each worm, and saccharose gradient versus physiological saline) on catecholamines and indolamines content in Nippostrongylus brasiliensis at various developmental stages (larvae and adults). Amines were determined by liquid chromatography with electrochemical detection. To the best of our knowledge, octopamine, tyramin, N-acetylserotonin and N-acetyldopamine were found and determined for the first time in this nematode. All experimental conditions listed above modify the endogenous amine levels in larval and adult Nippostrongylus brasiliensis. This should be taken into account in the design of future research protocols.

The effects of cutting gonapophyses were evaluated on the ovarian response two or four days after amputation in imaginai molt decapitated females Blaberus craniifer. Sites binding anti‐egg protein antibodies were detected in the periphery of basal oocytes in 68% operated females. In headless Blaberus craniifer, the onset of vitellogenesis which is triggered by extraphysiological doses of juvenile hormone or indolamines, was induced by this surgical procedure. It is suggested that amputation of gonapophyses affects the delivery of natural messengers inducing vitellogenesis at physiological concentration.

We developed a chromatographic system which separates cate-cholamines and indolamines as well as a large number of their metabolites (acids, aminoacids and glycols). Waters Radial Pak columns compressed radially to avoid formation of cavities in the packing, were used. These columns must be washed with methanol in order to obtain reproducible results when an ion-pairing mobile phase is employed. The conditioning of bhe columns was not affected by washing with triethylamine or variations in radial pressure. Good resolution of 13 samples was obtained in 28 minutes with a mobile phase composed of 0.1 M KH2PO4, 0.1 mM EDTA and 5 mM heptane sulfonic acid in water and Me OH (85:15), pH = 3.6. Products were identified with the use of a Metrohm 64l electrochemical detector. The technique was used for rapid, simultaneous determination of NA, DA, DOPAC, HVA, 5HT and 5HIAA in deproteinated mouse brain samples.