Transcription factor CREB3L1 regulates vasopressin gene expression in the rat hypothalamus.

Arginine vasopressin (AVP) is a neurohypophysial hormone regulating hydromineral homeostasis. Here we show that the mRNA encoding cAMP responsive element-binding protein-3 like-1 (CREB3L1), a transcription factor of the CREB/activating transcription factor (ATF) family, increases in expression in parallel with AVP expression in supraoptic nuclei (SONs) and paraventicular nuclei (PVNs) of dehydrated (DH) and salt-loaded (SL) rats, compared with euhydrated (EH) controls. In EH animals, CREB3L1 protein is expressed in glial cells, but only at a low level in SON and PVN neurons, whereas robust upregulation in AVP neurons accompanied DH and SL rats.

Effect of hyperosmotic stress on the gene expression and activity of neuronal nitric oxide synthase (nNOS) in the preoptic-hypothalamic neurosecretory system of the euryhaline fish Oreochromis mossambicus.

We examined the effects of hyperosmotic stress on the gene expression and activity of neuronal nitric oxide synthase (nNOS) in the preoptic/hypothalamic neurosecretory system of the euryhaline tilapia Oreochromis mossambicus (Mozambique tilapia) by means of semiquantitative RT-PCR and NADPHd histochemistry. Expression of nos1 was rapidly and transiently up-regulated in the preoptic region and hypothalamus in response to a salinity change (70% seawater, SW). Expression levels increased 4 h after the salinity change and then returned to basal levels within 8 h of the hyperosmotic challenge.

Partial cloning of neuronal nitric oxide synthase (nNOS) cDNA and regional distribution of nNOS mRNA in the central nervous system of the Nile tilapia Oreochromis niloticus.

A constitutive NOS complementary DNA (cDNA) was partially cloned by RT-PCR from the brain of a teleost, the Nile tilapia (Oreochromis niloticus), using degenerate primers against conserved regions of NOS. The predicted 206-long amino acid sequence showed a high degree of identity with other vertebrate neuronal NOS (nNOS) protein sequences. In addition, phylogenetic analysis revealed that Nile tilapia NOS clustered with other known nNOS.

Co-localization of neuronal nitric oxide synthase with arginine-vasotocin in the preoptic-hypothalamo-hypophyseal system of the teleost Oreochromis niloticus.

This study provides evidence that, in the preoptic-hypothalamo-hypophysial system of the teleost Oreochromis niloticus, several sub-populations of arginine-vasotocin (AVT)-producing neurons and neurosecretory fibers terminals express neuronal nitric oxide synthase (nNOS)-like molecules. The co-localization between nNOS and AVT was demonstrated by means of double immunofluorescence staining with the confocal microscope. This study is the first to provide evidence that nNOS may be co-localized with AVT in neurons of a non-mammalian vertebrate.

Expression of nitric oxide synthase in the preoptic-hypothalamo-hypophyseal system of the teleost Oreochromis niloticus.

In the present study, we have analyzed the expression of nitric oxide synthase (NOS) in the preoptic-hypothalamo-hypophyseal system of the teleost Oreochromis niloticus. The assay for enzyme activity demonstrated that a constitutive NOS activity is present both in soluble and particulate fractions of the homogenates of diencephalons. Western blot analysis using an antibody against the N-terminus of human nNOS revealed two bands both in the supernatant and in the pellet.

Nitric oxide and neuromodulation in the caudal neurosecretory system of teleosts.

Although evidence exists that nitric oxide (NO) mediates neuroendocrine secretion in mammals, the involvement of NO in the neuroendocrine regulation of non-mammalian vertebrates has yet to be investigated in detail. The present review conveys several recent data, suggesting that NO plays a modulatory role in the caudal neurosecretory system (CNSS) of teleosts. The presence and distribution of neuronal NO synthase (nNOS) was demonstrated in the CNSS of the Nile tilapia Oreochromis niloticus by means of NADPHd histochemistry, NOS immunohistochemistry, NOS immunogold electron microscopy, the citrulline assay for NOS activity and Western blot analysis.

Development of the caudal neurosecretory system of the nile tilapia Oreochromis niloticus: an immunohistochemical and electron microscopic study.

The development of the caudal neurosecretory system (CNSS) of the Nile tilapia, Oreochromis niloticus, has been investigated by means of UI/oCRF (urotensin I/ovine corticotropin-releasing factor) immunohistochemistry and transmission electron microscopy. UI-like immunoreactive perikarya and fibers are first detected in the caudal spinal cord of larval fish about 4 days after hatching (stage 21). In the region of the future urophysis two bundles of strongly immunoreactive neurosecretory fibers are observed.