Octopamine-like action of formamidines on hormone release in the locust, Locusta migratoria

Application of the formamidine pesticides chlordimeform (CDM) and desmethylchlordimeform (DCDM) induced the release of hyperlipemic hormone from the isolated corpus cardiacum (CC) of the locust, Locusta migratoria. Pretreatment of locusts with reserpine (10 μg/locust) had no effect on formamidine-induced release of the hyperlipemic hormone. The action of CDM and DCDM on isolated CC was blocked by the α-adrenergic-receptor blocker, phenoxybenzamine, but not by the β-adrenergic blocker, propranolol. These formamidines also potentiated the release of the hyperlipemic hormone induced by electrical stimulation of nervus corpus cardiacum II (NCC II). The evidence presented in this paper indicates that, in locusts, CDM and DCDM, or their metabolites, act on postsynaptic aminergic (octopamine) receptors in the glandular lobe of the CC, inducing the release of hyperlipemic hormone.