Neuropeptide Y effects on vasorelaxation and intestinal contraction in the Atlantic cod Gadus morhua

The Interplay between Central and Peripheral Systems in Feed Intake Regulation in European Seabass (Dicentrarchus labrax) Juveniles

The present study aimed to evaluate the effects of feeding or feed deprivation on the orexigenic and anorexigenic responses at the central (whole brain) and peripheral (anterior and posterior intestine, stomach, and liver) system levels in European seabass. For this purpose, a group of fish (208 g) was fed a single meal daily for 8 days (fed group) and another group was feed-deprived for 8 days (unfed group). Compared to the fed group, in the whole brain, feed deprivation did not induce changes in npy, agrp1, and cart2 expression, but increased agrp2 and pomc1 expression. In the anterior intestine, feed deprivation increased cck expression, while in the posterior intestine, the npy expression increased and pyyb decreased. In the stomach, the ghr expression decreased regardless of the feeding status. The hepatic lep expression increased in the unfed fish. The present results suggest a feed intake regulation mechanism in European seabass similar to that observed in other teleosts.

Molecular cloning, tissue distribution, and effect of fasting and refeeding on the expression of neuropeptide Y in Channa argus

Neuropeptide Y (NPY) is a 36 amino-acid amidated peptide of the pancreatic polypeptide (PP) family, which plays an important role in appetite regulation and energy expenditure in mammals. Although several teleost NPY have been identified, its roles remain unclear in fish. We herein reported on the molecular cloning, tissue distribution and the effect of fasting on the expression of NPY in Channa argus, and designated as CaNPY. It consisted of a 300 bp open reading frame predicted to encode a prepro-NPY of 99 amino acids. Sequence analysis revealed that CaNPY was highly conserved (>60%) with other vertebrate NPY. Phylogenetic analysis highly supported CaNPY was closely related to piscine NPY. In addition, except for muscle and spleen tissues, CaNPY was found to extensively expressed in all other detected tissues, with the highest level in brain. Futhermore, the CaNPY transcript was found to significantly increase after short-term and long-term food deprivation, and dramatically decrease following refeeding. These findings suggested that CaNPY might be involved in food intake regulation and it could be as a potential target locus to improve commercial production of this kind of fish.

The Relationship between VEGFA and TGFB1 Polymorphisms and Target Lesion Revascularization after Elective Percutaneous Coronary Intervention

Background and Aim

The specific association between genetic variation and in-stent restenosis is still only partly understood. The aim of this study is to analyze the relationship between functional polymorphisms in the genes encoding vascular endothelial growth factor A (VEGF-A; rs699947) and transforming growth factor beta 1 (TGF-β1; rs1800470) and target lesion revascularization (TLR) risk.

Methods

A total of 676 patients (805 lesions) with stable coronary artery disease (SCAD) who received elective percutaneous coronary intervention (PCI) with at least one bare-metal stent implantation were included. The primary study endpoint was TLR at a 4-year follow-up.

Results

The TLR rate was higher in patients with the VEGFA A/A genotype (15.4%) than in patients with the VEGFA A/C (7.9%) and C/C (8.9%) genotypes (p = 0.009). The VEGFA A/A genotype, after adjustment for clinical and procedural covariates, remained significantly and independently associated with the TLR (hazard ratio—2.09 [95% confidence interval 1.32–3.33, p = 0.0017]). However, we found no association between TLR and the TGFB1 genotype.

Conclusion

The VEGFA A/A genotype is significantly and independently associated with TLR risk in Polish SCAD patients who received elective PCI with bare-metal stent implantation.

Stimulatory effects of neuropeptide Y on the growth of orange-spotted grouper (Epinephelus coioides)

Neuropeptide Y (NPY) is a member of the pancreatic polypeptide family which is a potent orexigenic peptide known to date in mammals and teleost. This study was carried out to investigate the effects of NPY on food intake and growth of orange-spotted grouper (Epinephelus coioides). Synthetic grouper NPY (gNPY) was given orally at the dose of 0.5, 1.0 and 2.0 μg/g feed for 50 days, results showed that NPY treatment (1.0 and 2.0 μg/g feed) significantly increased growth rate, weight gain, feed conversion efficiency (FCE) and pituitary growth hormone (GH) mRNA level than the control group (p<0.05). Furthermore, high level secretion of gNPY was expressed and purified in the Pichia pastoris expression system. The bioactivity of recombinant gNPY was confirmed by its ability to up-regulate GH mRNA expression in vivo and in vitro and down-regulate preprosomatostatin I (PSSI) mRNA expression in vivo. These results demonstrate that NPY has stimulatory effects on food intake as well as growth of grouper as in other teleost fish, also indicate that recombinant gNPY from P. pastoris has the same bioactivity as synthetic gNPY and has the potential to be used as a feed additive for both research and aquatic application.

Characterization of neuropeptide Y in snakeskin gourami and the change in its expression due to feeding status and melanocortin 4 receptor expression

In this study, we characterized the neuropeptide Y (NPY) mRNA in snakeskin gourami (Trichogaster pectoralis) (TpNPY). TpNPY displayed characteristics typical of previously reported NPYs, and it exhibited a high degree of homology with the NPY proteins of other vertebrates. A phylogenetic analysis demonstrated that TpNPY was closely related to the NPYs found in the acanthomorpha and salmoniformes fish species. TpNPY was found to be ubiquitously expressed in all brain regions when assessed by real-time RT-PCR and in situ hybridization. In addition, a graded expression level of TpNPY was observed in peripheral tissues; for example, a moderate level of TpNPY was found in the gills, liver, kidney, stomach, intestine, spleen and gonads, while a low level of TpNPY was found in the muscle. The change in expression of TpNPY with respect to daily feeding habits was investigated in distinct brain regions, including the telencephalon, mesencephalon, metencephalon, and diencephalon. Fluctuations in the expression level of TpNPY were observed for a 24h post-prandial period. Except for the telencephalon, a reduction in TpNPY expression was found after a meal, while a peak level of TpNPY was observed 1h before the scheduled breakfast. Furthermore, there was a positive correlation between TpNPY and TpMC4R in the telencephalon and diencephalon throughout the circadian feeding cycle, which suggests that there is a connection between the function of NPY and the melanocortin system for the regulation of daily feeding. Fish brains were incubated with an MC4R antagonist (i.e., HS024), and the expression of TpNPY and TpMC4R was measured. Interestingly, there was a significant relationship between the expression of TpNPY and TpMC4R under the effects of HS024, which demonstrates that there are interactions between MC4R and NPY, particularly in a hyperphagic state.

Neuropeptide Y stimulates food intake in the Zebrafish, Danio rerio

Neuropeptide Y (NPY) is a potent orexigenic neuropeptide implicated in feeding regulation in mammals. However, except for the case of the goldfish, the involvement of NPY in the feeding behaviour of teleost fish has not well been studied. Therefore, we investigated the role of NPY in food intake using a zebrafish (Danio rerio) model because the molecular bases of NPY and its receptor have been well studied in this species. We examined the effect of feeding status on NPY-like immunoreactivity and the expression level of the NPY transcript in the brain. The number of neuronal cells showing NPY-like immunoreactivity in the hypothalamic regions, including the periventricular nucleus of posterior tuberculum and the posterior tuberal nucleus, was significantly increased in fish fasted for 7 days. NPY mRNA levels in the hypothalamus, but not the telencephalon, obtained from fish fasted for 7 days were higher than those in fish that had been fed normally. We then investigated the effect of i.c.v. administration of NPY on food intake. Cumulative food intake was significantly increased by i.c.v. administration of NPY (at 1 and 10 pmol/g body weight; BW) during a 60-min observation period. The NPY-induced orexigenic action (at 10 pmol/g BW) was blocked by treatment with a NPY Y1 receptor antagonist, BIBP-3226, at 100 pmol/g BW. These results indicate that NPY acts as an orexigenic factor in the zebrafish.

Brain neuropeptides in central ventilatory and cardiovascular regulation in trout

Many neuropeptides and their G-protein coupled receptors (GPCRs) are present within the brain area involved in ventilatory and cardiovascular regulation but only a few mammalian studies have focused on the integrative physiological actions of neuropeptides on these vital cardio-respiratory regulations. Because both the central neuroanatomical substrates that govern motor ventilatory and cardiovascular output and the primary sequence of regulatory peptides and their receptors have been mostly conserved through evolution, we have developed a trout model to study the central action of native neuropeptides on cardio-ventilatory regulation. In the present review, we summarize the most recent results obtained using this non-mammalian model with a focus on PACAP, VIP, tachykinins, CRF, urotensin-1, CGRP, angiotensin-related peptides, urotensin-II, NPY, and PYY. We propose hypotheses regarding the physiological relevance of the results obtained.

Sympathetic, parasympathetic and enteric regulation of the gastrointestinal vasculature in rainbow trout (Oncorhynchus mykiss) under normal and postprandial conditions

The control of the gastrointestinal hyperemia that occurs after feeding in most animals is of fundamental importance for the subsequent absorption, metabolism and redistribution of nutrients. Yet, in fish, it has received little attention and the nature of it is far from clear. We sought to investigate the importance of extrinsic and intrinsic innervation of the gastrointestinal tract in the regulation of gastrointestinal blood flow in rainbow trout (Oncorhynchus mykiss). The contribution of the extrinsic innervation, i.e. by the sympathetic and the parasympathetic nervous system, was examined by comparing the response to the injection of a predigested nutrient diet into the proximal intestine of untreated fish with the response in fish in which the splanchnic and vagal innervation of the gut had been removed. We also injected the predigested nutrient diet into anaesthetized fish treated with tetrodotoxin that would block the intrinsic innervation of the gut (i.e. enteric nervous system). Our results confirm the notion that the sympathetic portion of the extrinsic innervation maintains the basal vascular tone, but neither the splanchnic nor the vagal innervation is fundamental to the postprandial hyperemia. However, the tetrodotoxin treatment completely abolished the postprandial hyperemia, indicating the importance of the enteric nervous system. In conclusion, it seems as though the enteric nervous system is essential to the regulation of the postprandial hyperemia, and that the extrinsic innervation is involved mainly in the regulation of gastrointestinal blood flow under normal conditions and in response to central coordination with other organs.

Autonomic control of gut motility: a comparative view

Gut motility is regulated to optimize food transport and processing. The autonomic innervation of the gut generally includes extrinsic cranial and spinal autonomic nerves. It also comprises the nerves contained entirely within the gut wall, i.e. the enteric nervous system. The extrinsic and enteric nervous control follows a similar pattern throughout the vertebrate groups. However, differences are common and may occur between groups and families as well as between closely related species. In this review, we give an overview of the distribution and effects of common neurotransmitters in the vertebrate gut. While the focus is on birds, reptiles, amphibians and fish, mammalian data are included to form the background for comparisons. While some transmitters, like acetylcholine and nitric oxide, show similar distribution patterns and effects in most species investigated, the role of others is more varying. The significance for these differences is not yet fully understood, emphasizing the need for continued comparative studies of autonomic control.

Cloning and characterization of neuropeptide Y (NPY) and cocaine and amphetamine regulated transcript (CART) in Atlantic cod (Gadus morhua)

Neuropeptide Y (NPY) and cocaine and amphetamine regulated transcript (CART) are two neuropeptides involved in the regulation of feeding in both mammals and fish. NPY stimulates feeding whereas CART inhibits feeding. In this study, we have cloned the full-length cDNA and complete genomic DNA sequences for NPY and CART in Atlantic cod. Atlantic cod preproNPY share a 45-85% identity with preproNPY from other fish whereas preproCART shows a 70% identity to CART peptides from zebrafish and goldfish. RT-PCR revealed that NPY mRNA is expressed in brain, in particular the forebrain, and in peripheral tissues, including intestine and kidney. CART mRNA is expressed throughout the brain and in ovaries. In order to assess the role of these peptides in the regulation of feeding, we examined changes in mRNA expression in the forebrain before, during and after a meal. NPY and CART mRNA both undergo peri-prandial changes in expression, with NPY levels being elevated around meal time and CART showing a decline 2 h after a meal. Food deprivation for 7 days induced a decrease in CART mRNA expression in the brain but did not affect NPY mRNA expression. Overall, our results suggest that NPY and CART are conserved peptides that might be involved in the regulation of feeding and other physiological functions in Atlantic cod.

Structure and autonomic innervation of the swim bladder in the zebrafish (Danio rerio)

Many teleosts actively regulate buoyancy by using a gas-filled swim bladder, which is thought to be under autonomic control. Here we investigated the swim bladder in the zebrafish to determine possible mechanisms of gas-content regulation. Fluorescently labelled phalloidin revealed myocytes that appeared to form a possible sphincter at the junction of the pneumatic duct and esophagus. Myocytes also formed thick bands along the ventral surface of the anterior chamber and bilaterally along the posterior chamber. Thinner layers of myocytes were located elsewhere. Staining of peroxidase within erythrocytes revealed a putative rete and smaller blood vessels in muscle bands and elsewhere. The antibodies zn-12, a general neuronal marker, and SV2, a synaptic vesicle marker labelling presynaptic terminals, revealed widespread innervation of the swim bladder system. Widespread innervation of the swim bladder was also indicated by acetylcholinesterase histochemistry, but choline acetyltransferase-immunoreactive (-IR) somata and fibers were limited to the junction of the pneumatic duct and esophagus. In contrast, varicose tyrosine hydroxylase-IR fibers innervated muscles and blood vessels throughout the system. Neuropeptide Y-IR somata were located near the junction of the duct and esophagus and varicose fibers innervated muscles and vasculature of the posterior chamber and duct. Vasoactive intestinal polypeptide immunoreactivity was abundant throughout the anterior chamber but sparsely distributed elsewhere. Serotonin-IR fibers and varicosities were located only along blood vessels near the junction of the pneumatic duct and posterior chamber. Our results suggest that the zebrafish swim bladder is a complex and richly innervated organ and that buoyancy-regulating effectors may be controlled by multiple populations of autonomic neurons.