LEVELS OF BIOGENIC-AMINES AND PEPTIDES IN INDIVIDUAL CORN-EARWORM MOTHS, HELICOVERPA-ZEA, USING HIGH-PERFORMANCE LIQUID-CHROMATOGRAPHY WITH ELECTROCHEMICAL DETECTION

Quantitative levels of octopamine, serotonin, and dopamine were measured from brain and corpus cardiacum in individual male and female Helicoverpa zea, using high performance liquid chromatography (HPLC) with electrochemical detection. By increasing the proportion of organic modifiers in the mobile phase we were also able to quantify two peptides, adipokinetic hormone and hypertrehalosemic hormone. Levels of amines in both tissues were similar in males and females, but with greater quantities in the brain than the corpus cardiacum. In contrast, the two hormones were found predominantly in the corpus cardiacum, with the level of adipokinetic hormone three times greater than that of the hypertrehalosemic hormone, a finding in agreement with other studies. The described methodology demonstrates the power of HPLC with electrochemical detection for analysis of amines and peptides found in small quantities within the nervous tissue of individual insects.