Ultrastructural analysis of the action of reserpine on the brain neuroendocrine system of the wax moth, Galleria mellonella L., Lepidoptera

Further evidence for norepinephrine as a neurotransmitter stimulating release of melanin-dispersing hormone in the fiddler crab, Uca pugilator: the changes in the melanophores of the crabs following reserpine, 6-hydroxydopamine and bretylium administration

1. The effects on the melanophores of the fiddler crab, Uca pugilator, of the amine depletor reserpine, the catecholamine neurotoxin 6-hydroxydopamine and the noradrenergic neuron blocker bretylium were investigated. 2. The most striking effect of these drugs was that they strongly reduced the amount of melanin dispersion that normally results on transferring the crabs from a white to a black background. the drugs had no effect on pigment migration in melanophores of isolated legs. These results are in accord with the hypothesis that norepinephrine serves as a neurotransmitter stimulating release of a melanin-dispersing hormone in Uca pugilator. 3. Norepinephrine was found in the central nervous system of Uca pugilator.

Effect of disulfiram on the ultrastructure of the peptidergic and aminergic cells in the pars intercerebralis of Galleria mellonella (Lepidoptera)

Injection of disulfiram, a specific inhibitor of noradrenaline synthesis, evokes changes in two different types of neurons in the brain of Galleria mellonella: neurones containing dense-core vesicles (60-80 nm) and peptidergic cells containing 180-200 nm neurosecretory granules. The lowering of the electron density of the dense-core vesicles of 60-80 nm seems to be directly connected with disulfiram administration, while the decrease of the amount of neurosecretory material in the neurosecretory cells of type I seems to be a secondary effect of the drug injection. The participation of noradrenaline in the regulation of the secretory activity of type I peptidergic neurosecretory cells of the pars intercerebralis is postulated.

Effect of reserpine on the larval-pupal moult of the wax moth Galleria mellonella L. (Lepidoptera)

Significant retardation of G. mellonella development was induced by reserpine injected to the last instar larvae in doses having a long-lasting effect on the neurosecretory system.