The anterior aorta is rich in axons and axonal endings originating from the nervus corporis cardiacum (NCC) and the corpus cardiacum (CC). Neurosecretory granules in the NCC axons are small compared to large granules synthesized in the CC. Vesiculation of the secretory granules into clusters of small vesicles occur both in NCC axonal endings and axon-like processes from the CC, suggesting that both types of secretions are released into the haemolymph.

Synapses occur between the NCC axons and cardiac muscle cells, as well as with cell processes from the CC, suggesting that some of the neurohormes from the NCC axons may function as neurotransmitters. The CC consists of large neuron-like cells, that synthesize an intrinsic secretion; it also contains a neuropil of NCC axons and CC cell processes. There is no evidence of a separate storage and release lobe in the CC. No synapses occur between the axons and cell processes or with the cell bodies. The CC cell processes have their endings in the aortic wall where they make synapses with NCC axonal endings and where they most likely release their material. It is suggested that in Glossina: (a) the aortic wall has taken over the neurohaemal role of the CC whose function otherwise remains that of synthesizing an intrinsic hormone; and that (b) the activity of the CC to synthesize and/or release its intrinsic secretion is most likely controlled in the aortic wall via a neurotransmitter substance.