Studies on the neurosecretory system and the functional significance of NSM in the aortal wall of the bug, Dysdercus koenigii

Abstract

The neurosecretory system of the bug, Dysdercus koenigii is described with the help of PF, PAVB, PATh in situ preparations, and sections. There are two groups of 9 to 10 A-cells in the pars intercerebralis medialis, and the NSM elaborated by them is found to be positive to cystine and/or cysteine. Their neurosecretory pathways immediately after formation cross each other and emerge as NCC I from the tritocerebrum. The NCC I run dorsal to the corpora cardiaca and innervate the aorta wall after completely bypassing these glands. NSM, elaborated by the A-cells and transported by their axons, is found in ample quantity in the aorta wall and the latter is therefore considered to be the neurohaemal organ for the A-material. Four to six B-cells are present in each pars intercerebralis lateralis, and their axons form NCC II after running directly and emerging also from the tritocerebrum. Distally the NCC II join the corpora cardiaca, and, on the basis of B-cell type material in the glands, they are considered as the storage-and-release organs for the B-material. The corpora cardiaca are not associated with the aorta wall and are found to be devoid of A-cell NSM. It is suggested that in D. koenigii two independent organ complexes: (1) the A cells, their pathways, and the aorta wall and (2) the B-cells, their pathways, and the corpora cardiaca constitute the neurosecretory system. The probable physiological significance of this anomaly is discussed.