Daphnia longicephala neuropeptides: morphological description of crustacean cardioactive peptide (CCAP) and periviscerokinins in the Ctenodaphnia central nervous system.

The publication of the Daphnia genome has driven research in this ecologically relevant model organism in many directions. However, information on this organism's physiology and the relevant controlling factors is limited. In this regard, especially neuropeptides are important biochemical regulators that control a variety of cellular processes, which in combination influence physiological conditions and allow the adaptation of the internal physiological state to external conditions.

Morphology of the Daphnia nervous system: a comparative study on Daphnia pulex, Daphnia lumholtzi, and Daphnia longicephala.

The freshwater crustacean Daphnia is well known for its phenotypic plasticity, in which environmental cues are perceived by the nervous system and transformed into phenotypic adaptations beneficial under current conditions. Critical knowledge regarding the distribution and localization of neuronal antigens or neurotransmitters and differentially expressed proteins is sparse. Here, we applied immunohistochemical and histological-staining methods in combination with confocal laser scanning microscopy on whole mount preparations in Daphnia pulex, Daphnia longicephala, and Daphnialumholtzi.

Developmental expression of neuromodulators in the central complex of the grasshopper Schistocerca gregaria.

The central complex is a major integrative region within the insect brain with demonstrated roles in spatial orientation, the regulation of locomotor behavior, and sound production. In the hemimetabolous grasshopper, the central complex comprises the protocerebral bridge, central body (CB), ellipsoid body, noduli, and accessory lobes, and this modular organization develops entirely during embryogenesis. From a biochemical perspective, a range of neuroactive substances has been demonstrated in these modules of the adult central complex, but little is known about their developmental expression.

Cell death shapes embryonic lineages of the central complex in the grasshopper Schistocerca gregaria.

We have investigated cell death in identified lineages of the central complex in the embryonic brain of the grasshopper Schistocerca gregaria. Progeny from these lineages lie in the pars intercerebralis and direct projections to the protocerebral bridge and then the central body via the w, x, y, z tracts. Osmium-ethyl gallate staining reveals pycnotic cells exclusively in cortical regions, and concentrated specifically within the lineages of the W, X, Y, Z neuroblasts.

Proliferative cell types in embryonic lineages of the central complex of the grasshopper Schistocerca gregaria.

The central complex of the grasshopper Schistocerca gregaria develops to completion during embryogenesis. A major cellular contribution to the central complex is from the w, x, y, z lineages of the pars intercerebralis, each of which comprises over 100 cells, making them by far the largest in the embryonic protocerebrum. Our focus has been to find a cellular mechanism that allows such a large number of cell progeny to be generated within a restricted period of time.

Multipotent neuroblasts generate a biochemical neuroarchitecture in the central complex of the grasshopper Schistocerca gregaria.

We have examined the developmental expression of the neuromodulators locustatachykinin, leucokinin-1, allatostatin and serotonin in a subset of lineages (Y, Z) of the central complex in the brain of the grasshopper Schistocerca gregaria. First, we show that all these neuromodulators are expressed in the same lineages during embryogenesis. The neuroblasts generating these lineages are therefore biochemically multipotent.

Identification of novel neuropeptides in the ventral nerve cord ganglia and their targets in an annelid worm, Eisenia fetida.

Periviscerokinins (PVKs) and pyrokinins (PKs) are neuropeptides known in several arthropod species. Sequence homology of these peptides with the molluscan small cardioactive peptides reveals that the occurrence of PVKs and PKs is not restricted to arthropods. Our study focuses on the biochemical and immunocytochemical identification of neuropeptides with sequence homology to PVKs and PKs in the central and peripheral nervous system of the earthworm Eisenia fetida.

Changes in the expression of PACAP-like compounds during the embryonic development of the earthworm Eisenia fetida.

Pituitary adenylate cyclase-activating polypeptide (PACAP) is expressed at very early stages in the vertebrate nervous system, and its functions in the embryonic development have been shown by various studies. PACAP is an extremely conserved molecule in phylogeny; however, little is known about its presence and functions in invertebrates. Our previous studies have shown the occurrence of PACAP-like immunoreactivity in the invertebrate nervous system.

Identification of sex hormone-binding globulin in the human hypothalamus.

Gonadal steroids are known to influence hypothalamic functions through both genomic and non-genomic pathways. Sex hormone-binding globulin (SHBG) may act by a non-genomic mechanism independent of classical steroid receptors. Here we describe the immunocytochemical mapping of SHBG-containing neurons and nerve fibers in the human hypothalamus and infundibulum.

Co-expression of vasopressin and androgen-binding protein in the rat hypothalamus.

In previous studies we have observed the expression of androgen binding protein (ABP) in the rat hypothalamo-neurohypophysial system. With immunocytochemical double staining we found partial co-localization with oxytocin. In the present study we used antibodies to the anti-diuretic hormone arginine vasopressin (AVP) for co-localization with ABP in the rat hypothalamus.

Neuropeptides in perisympathetic organs of Manduca sexta: specific composition and changes during the development.

We used a combination of matrix-assisted laser desorption-ionization time-of-flight mass spectrometry and immunocytochemistry to investigate the peptides from abdominal perisympathetic organs of Manduca sexta. Altogether three mass peaks, detected in mass spectra from single abdominal perisympathetic organs were identical with already known neuropeptides, namely CAP(2b), CCAP, and Manduca-allatotropin. Only CAP(2b) was found throughout the postembryonic development.

Distribution of androgen-binding protein in the rat hypothalamo-neurohypophyseal system, co-localization with oxytocin.

Androgen-binding protein (ABP) is known to be expressed in the male and female rat hypothalamus. In the present study, we observed immunocytochemically ABP in neurons of the magnocellular hypothalamic nuclei, in the preoptic region and in the lateral hypothalamus. Dense fiber networks with varicosities, containing ABP immunofluorescence, were visible throughout the hypothalamus, the median eminence and in the posterior pituitary lobe.

Estradiol control of expression and levels of estradiol-binding proteins in the medial preoptic area, medial hypothalamus and pituitary.

The brains of mammals have at least three estradiol-binding proteins: estradiol receptor-alpha (ERalpha), ERbeta, and sex hormone-binding globulin (SHBG). In this study we compare the effects of estradiol treatment on the expression of mRNA for these three estradiol-binding proteins in two reproductively important brain areas, the medial preoptic area-anterior hypothalamus (MPOA-AH) and medial hypothalamus (MH) as well as in the hippocampus in ovariectomized rats, using the reverse transcriptase-polymerase chain reaction (RT-PCR). We also used surface-enhanced laser desorption ionization time of flight (SELDI-TOF) mass spectrometry (MS) to analyze the effects of estradiol in ovariectomized rats on SHBG levels in the MPOA-MH as well as the neurohypophysis.

Identical cellular distribution of all abundant neuropeptides in the major abdominal neurohemal system of an insect (Periplaneta americana).

The median neurosecretory cells in abdominal ganglia of insects synthesize a number of putative hormones, which are abundant in the abdominal perisympathetic organs (PSOs). The peptide inventory of these prominent neurohemal release sites is best investigated in the American cockroach and strongly differs from that of head/thoracic neurohemal organs. In this study, we found a complete colocalization of all abundant neuropeptides in this hormonal system, including periviscerokinin-1 and -2, pyrokinin-5, YLSamide, VEAacid, and SKNacid.

The periviscerokinin (PVK) peptide family in insects: evidence for the inclusion of CAP(2b) as a PVK family member.

Periviscerokinins (PVKs) are a distinct insect peptide family with unusual distribution in the central nervous system and neurohemal release sites. PVKs were first isolated from the abdominal perisympathetic organs of Periplaneta americana, but can be found in other insect species. Peptides with structural similarity to PVKs have been identified through searches of the Drosophila genome.