Neurosecretory system

Contrasting results have also been obtained with different species of Mesocestoides. In M. corti, the chief factors inducing strobilar differentiation in vitro appear to be anaerobic conditions (Fig. 10.12, p. 280) and a pH greater than 7.4 (606,607,806). Yet in M. lineatus, the presence of trypsin in the culture media is required for sexual differentiation (382). These phenomena are discussed in further detail in Chapter 10. Whatever the nature of the stimulus which initiates sexual differentiation, there is now strong experimental evidence that it operates via the neurosecretory system. It was speculated, many years ago, that in E. granulosus, the contact stimulus operated via a neurosecretion which in turn induced the release of a strobilisation organiser (796). 

Activation of the peptidergic neurosecretory system in Diphyllobothrium dendriticum (Cestoda Pseudophyllidea). Parasitology, 83 243-7. 

Whitnall MH (1993) Regulation of the hypothalamic corticotropin-releasing hormone neurosecretory system. Prog Neurobiol 40 573-629. 

Fox RI, Stern ME. Sjogren s syndrome mechanisms of pathogenesis involve interaction of immune and neurosecretory systems. Scand J Rheumatol 2002 116 3-13. 

Bern, H.A., Pearson, D., Larson, B.A. and Nishioka, R.S. (1985) Neurohormones from fish tails the caudal neurosecretory system. I. Urophysiology and the caudal neurosecretory system of fishes. Recent. Prog. Horm. Res. 41 533-552. 

Many hormones are rich in cysteine and the tissues in which they accumulate can be easily recognized by a marked uptake of S-L-cysteine. For instance, mature virgin mice, mature mice of both sexes and castrated males display a S-labelled juxtamedullary X-zone in the brain, whereas normal adult male mice do not . The neurosecretory system of the earthworm markedly accumulates cysteine- S The neurosecretory cells of rapidly developing female locusts and females in the second gonotropic cycle take up cysteine- S at a greater rate than either newly emer d or slowly developing females . 

All these features have made the cockroach neurosecretory system our favorite model for direct tissue (neuro)secretory peptide investigations, for many years (2). 

The mechanism of acute O2 sensing based on the regulation of membrane K" " channels seems to be a rather general phenomenon that has been shown to operate in other neurosecretory systems, such as the cells in the neuroepithelial bodies of the Ixmg (18), chromaffin cells of the adrenal medulla (19), or PC 12 cells... 

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