Locations and central projections of neurons associated with the retrocerebral neuroendocrine complex of the cockroach Periplaneta americana (L.)

Abstract

Retrograde diffusion and precipitation of Co2+ reveals in the ipsilateral pars lateralis (PL) and contralateral pars intercerebralis (PI) of the brain neurons that enter the corpus cardiacum (CC), and, possibly, the corpus allatum (CA) on each side. The PL group consists of 29.6 +/- 8.4 somata that fill. Of these, 5.6 +/- 0.6 exceed 25 micrometer in diameter, 14.3 +/- 2.7 range from 15--25 micrometer, and 9.6 +/- 7.6 are smaller than 15 micrometer. After CoCl2 was applied to the right CC-CA of two males, 239 and 265 somata in the left PI stained. Except for 16 ranging from 30--45 micrometers and chiefly located anteriorly, a majority of these somata measured 10--25 micrometer. The only somata revealed by staining whole brains with the performic acid-resorcin fuchsin method are neurosecretory cells 10--20 micrometer in diameter located within the PI. In starved adult males there are 92.4 +/- 8.1 on the right, and 93.2 +/- 6.9 on the left. The largest somata in the PL group contain numerous granules that stain with paraldehyde fuchsin. These somata also fill with Co2+, and belong to neurosecretory cells that extend into the CC-CA. The cerebral distribution of branches from the PL group, and the relationship of these to the corpora pedunculata, central body, and arborizations from the PI decussation are described.

The neuroendocrine system of invertebrates: a developmental and evolutionary perspective

“…The majority of NSCs are found in the dorso-medial protocerebrum, the so-called pars intercerebralis (PI) and pars lateralis (PL; Pipa 1978, Raabe 1989, Schooneveld 1998, Veelaert et al 1998, Siegmund & Korge 2001. These NSCs project their axons toward a set of endocrine glands, the corpora cardiaca (CC) and corpora allata (CA; Fig.…”

Peptidergic neurohemal system of an insect: Mass spectrometric morphology

“…Several neurosecretory cell groups in the brain and subesophageal ganglion are known to synthesize peptidergic neurohormones that are transported by means of different nerves into the retrocerebral complex (Pipa, 1978;Gundel and Penzlin, 1980). The major neurohemal tissue of the retrocerebral complex is the storage part of the corpus cardiacum (CC).…”

Identification of the cerebral neurosecretory cells that contain eclosion hormone in the moth Manduca sexta

“…These results strongly indicated that at least some of the protocerebral neurosecretory cells (but not the tritocerebral clusters) produce biologically active EH. Since numerous studies have found significant amounts of neurosecretory material in the dendrites and central processes of insect peptidergic cells (Agricola et al, 1985;Geldiay and Edwards, 1973;Pipa, 1978;Veenstra et al, 1985), we chose the more rigorous approach of single-cell dissections to identify the clusters that produce EH. As previously noted, the large protocerebral neurosecretory cells in the developing adult moth brain are clearly visible (Fig.…”