Benelux Congress of Zoology edition:8 location:Nijmegen date:23-24 November
The corpora cardiaca (CC) together with the pars intercerebralis, which is a well-defined area in the insect brain, are probably the most important part of the neuroendocrine system in insects. The pars intercerebralis-corpora cardiaca complex is comparable with the hypothalamus-pituitary complex in mammals.
Four-day-old adult male and female locusts were decapitated. The CC were dissected and cleaned in insect saline buffer (ISB). Each group containing 20 CC was perifused for half an hour with ISB to measure spontaneous release (control condition). Subsequently the same group was perifused for half an hour with ISB that contained an elevated potassium concentration or a catecholamine (experimental condition). The released peptides in each condition were collected and concentrated on single use C18 columns. These single use columns were eluted with 30 % ACN, 60 % ACN and 90 % ACN in aqueous TFA (0.1 %). The components present in these three crude fractions were further separated on a capillary HPLC system (Waters CapLC). The implemented software made an easy comparison of the quantity of the different components in the control and the experimental condition possible. Our data indicates that an elevated potassium concentration as well as addition of catecholamines to the perifusion fluid has an effect on the secretion of substances by the CC into the perifusion medium. Specific peaks of the CC peptide profile differ significantly in quantity (based on peak area) while others remained unaffected. The identity of these peaks remains unknown so far.