Nitric oxide synthase in the caudal neurosecretory system of the teleost Oreochromis niloticus

Cioni, Carla; Greco, Alessandra; Pepe, A.; Vito, Luana De; Colasanti, Marco

doi:10.1016/s0304-3940(97)00857-4

Cited by 14 publications

(14 citation statements)

References 16 publications

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“…However, most of the neurosecretory cell bodies were NOS-labeled, confirming our previous histochemical analysis [Cioni et al, 1997]. Gold particles for nNOS were frequently aggregated in clusters of 3-7 particles.…”

Section: Resultssupporting

confidence: 89%

“…The present results confirm and extend our previous histochemical and immunohistochemical report on the localization of neuronal NOS in the CNSS of the same teleost [Cioni et al, 1997]. They also correlate well with available biochemical data.…”

Section: Discussionsupporting

confidence: 92%

“…Moreover, they both have hypophysiotropic and osmoregulatory effects in fish [Bern et al, 1985;Lederis et al, 1985]. We have recently localized neuronal NOS-like molecules in the caudal neurosecretory neurons and the urophysis of the teleost Oreochromis niloticus [Cioni et al, 1997]. Subsequent biochemical analysis has confirmed the presence of a constitutive NOS activity both in the supernatant and in the pellet of caudal spinal cord homogenates.…”

Section: Introductionmentioning

confidence: 84%

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Colocalization of Neuronal NO Synthase with Urotensins I and II in the Caudal Neurosecretory Neurons and the Urophysis of the Teleost Oreochromis niloticus

Cioni¹,

Vito²

2000

Brain Behav Evol

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The intracellular distribution of neuronal nitric oxide synthase (nNOS) was studied in the caudal neurosecretory system of a teleost, Oreochromis niloticus (Cichlids), by means of post-embedding immunogold labeling with a polyclonal antibody directed against nNOS of human origin. Ultrastructural examination demonstrated that neuronal NOS-like molecules are distributed within the Dahlgren cell perikarya, the neurosecretory axons, and the urophysial axon terminals. In the neurosecretory somata, gold particles for nNOS were mainly cytosolic, whereas in the neurosecretory axons and axon terminals they were associated with the membrane and/or the dense core of neurosecretory granules. Double immunogold labelings for nNOS/urotensin I (UI) and nNOS/urotensin II (UII) demonstrated that nNOS-like molecules are colocalized with UI and/or UII in the neurosecretory granules contained within the urophysial terminals. The present findings suggest that both a soluble cytosolic and a particulate neuronal NOS are expressed in the caudal neurosecretory neurons. They confirm previous biochemical data on the same species.

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Section: Resultssupporting

confidence: 89%

Section: Discussionsupporting

confidence: 92%

Section: Introductionmentioning

confidence: 84%

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Colocalization of Neuronal NO Synthase with Urotensins I and II in the Caudal Neurosecretory Neurons and the Urophysis of the Teleost Oreochromis niloticus

Cioni¹,

Vito²

2000

Brain Behav Evol

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“…With respect to the latter, nitric oxide (NO) has been implicated as a local neuromodulator in this system. Dahlgren cells in another teleost, Oreochromis niloticus, express nitric oxide synthase (Cioni et al, 1997) and in flounder we have shown that they are excited by application of a NO donor (Brierley et al, 2002). Thus, it is possible that Dahlgren cell activity is coordinated by local positive feedback, in a similar way to the synchronised high frequency bursts of oxytocin neurons (Russell et al, 2003).…”

Section: The Journal Of Experimental Biology Electrical Activity Of Dmentioning

confidence: 95%

Electrical activity of caudal neurosecretory neurons in seawater and freshwater-adapted Platichthys flesus, in vivo

Ashworth

Banks

Brierley

et al. 2005

Journal of Experimental Biology

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SUMMARY This study examined the electrical firing activity of neuroendocrine Dahlgren cells in the caudal neurosecretory system (CNSS) of the euryhaline flounder in vivo. Intracellular recordings revealed generally similar activity patterns and membrane properties to those previously reported in vitro. To investigate the potential role of the CNSS in osmoregulatory adaptation, extracellular, multiunit, recordings compared the activity patterns of Dahlgren cells in fully seawater- and freshwater-adapted fish. The proportion of cells showing bursting (as opposed to phasic or tonic) activity was greater in seawater-than in freshwater-adapted fish, as was the Correlation Index, a measure of the degree of correlation between firing activities of cells recorded simultaneously from the same preparation. Acute transfer of fish from seawater to freshwater gill perfusion led to recruitment of previously silent Dahlgren cells and a reduction in Correlation Index;freshwater to seawater transfer increased the Correlation Index. Severing the spinal cord anterior to the CNSS led to an increase in overall Dahlgren cell activity. Electrical stimulation of branchial nerve branches providing input to the brainstem, or tactile (pinch) stimulation of lips or fins, led to a reduction in CNSS activity lasting up to 500 s, indicating the presence of descending modulatory pathways from the brain. These results are consistent with a role for CNSS neuropeptides, urotensins, in supporting survival in a hypertonic, seawater, environment.

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“…We provided evidence for nNOS in the caudal neurosecretory system (CNSS) of Oreochromis niloticus [Cioni et al, 1997] by means of both NADPHd histochemistry and nNOS immunocytochemistry. Biochemical and Western blot analyses also indicated that a constitutive NOS is expressed in fish caudal spinal cord, which is similar to mammalian nNOS [Cioni et al, 1998].…”

Section: Introductionmentioning

confidence: 99%

Expression of Nitric Oxide Synthase in the Preoptic-Hypothalamo-Hypophyseal System of the Teleost Oreochromis niloticus

et al. 2003

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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. One band co-migrates at approximately 150 kDa with that detected in the rat cerebellum homogenates and presumably corresponds to neuronal NOS (nNOS) of mammals. The additional band, which migrates at approximately 180 kDa, might be attributed to an alternatively spliced nNOS isoform. Using NADPH diaphorase (NADPHd) histochemistry in combination with NOS immunohistochemistry, nNOS expression has been detected in preoptic nuclei, hypophysiotrophic nuclei of the ventral hypothalamus, and the pituitary gland. Various degrees of dissociation of NADPHd activity and nNOS immunoreactivity have been detected that could be attributed to the expression of different subtypes of nNOS in the preoptic/hypothalamo/hypophysial system of tilapia. In this paper, we also investigated the colocalization of nNOS with arginine-vasotocin (AVT) by means of immunolabeling of consecutive sections. Results suggest that NO may be colocalized with AVT in a subpopulation of neurosecretory neurons. Present findings suggest that nitric oxide (NO) is implicated in the modulation of hormone release in teleosts in a similar way to mammals.

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Nitric oxide synthase in the caudal neurosecretory system of the teleost Oreochromis niloticus

Cited by 14 publications

References 16 publications

Colocalization of Neuronal NO Synthase with Urotensins I and II in the Caudal Neurosecretory Neurons and the Urophysis of the Teleost <i>Oreochromis niloticus</i>

Colocalization of Neuronal NO Synthase with Urotensins I and II in the Caudal Neurosecretory Neurons and the Urophysis of the Teleost <i>Oreochromis niloticus</i>

Electrical activity of caudal neurosecretory neurons in seawater and freshwater-adapted Platichthys flesus, in vivo

Expression of Nitric Oxide Synthase in the Preoptic-Hypothalamo-Hypophyseal System of the Teleost <i>Oreochromis niloticus</i>

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