The involvement of the central cholinergic system in the hyperventilation effect of centrally injected nesfatin-1 in rats.

We recently demonstrated that peripheral and central administration of nesfatin-1 in fasting and satiety states generate hyperventilation activity by increasing tidal volume (TV), respiratory rate (RR), and respiratory minute ventilation (RVM). The present study aimed to investigate the mediation of central cholinergic receptors effective in respiratory control in the hyperventilation activity of nesfatin-1. Besides this, we intended to determine possible changes in blood gases due to hyperventilation activity caused by nesfatin-1 and investigate the mediation of central cholinergic receptors in these changes. Intracerebroventricular (ICV) administration of nesfatin-1 revealed a hyperventilation response with an increase in TV, RR, RMV, and pO2 and a decrease in pCO2 in saturated Sprague Dawley rats. ICV pretreatment with the muscarinic receptor antagonist atropine partially blocked the RR, RMV, pO2, and pCO2 responses produced by nesfatin-1 while completely blocking the TV response. However, central pretreatment with nicotinic receptor antagonist mecamylamine blocked the respiratory and blood gas responses induced by nesfatin-1. The study's conclusion demonstrated that nesfatin-1 had active hyperventilation effects resulting in an increase in pO2 and a decrease in pCO2. The critical finding of the study was that activation of central cholinergic receptors was involved in nesfatin-1-evoked hyperventilation and blood gas responses.

The intermediary role of the central cyclooxygenase / lipoxygenase enzymes in intracerebroventricular injected nesfatin-1-evoked cardiovascular effects in rats.

That nesfatin-1 is a neuromodulatory peptide for the cardiovascular system is well documented. Several central receptors have been shown to mediate the cardiovascular effects of nesfatin-1. Immunohistochemistry and Western blot studies showed that nesfatin-1 activated the expression of the central cyclooxygenase (COX) -1, -2 and lipoxygenase (LOX). In addition, microdialysis study showed that nesfatin-1 increased the release of total prostaglandins and leukotrienes from the hypothalamus. The present study investigated whether the central COX and LOX enzymes have a direct mediating role in the MAP and HR responses of nesfatin-1. Intracerebroventricularly administered nesfatin-1 produced dose-dependent pressor and phasic HR responses in normotensive conscious rats Sprague Dawley. Central pretreatment with a COX1/2 inhibitor, ibuprofen, completely blocked the nesfatin-1-induced responses. However, central pretreatment with a nonselective LOX inhibitor, nordihydroguaiaretic acid, partially attenuated the cardiovascular responses induced by nesfatin-1. The results suggest that centrally administered nesfatin-1 activates the central enzymes COX and LOX, which may be involved in the cardiovascular responses as a novel central mechanism for nesfatin-1.

Intracerebroventricularly injected nesfatin-1 activates central cyclooxygenase and lipoxygenase pathways.

Nesfatin-1 is a multifunctional neuropeptide having crucial autonomic roles. It is well known that nesfatin-1 collaborates with other central neuromodulatory systems, such as central corticotropin-releasing hormone, melanocortin, oxytocin, and cholinergic systems to show its autonomic effects. Central arachidonic acid cascade plays an important role to provide the homeostasis by exhibiting similar autonomic effects to nesfatin-1. Based on these similarities, the current study was designed to show the effects of intracerebroventricularly (ICV) injected nesfatin-1 on the hypothalamic arachidonic acid (AA) cascade. Immunochemistry and western blot approaches demonstrated that ICV administration of nesfatin-1 provokes an increase in the hypothalamic cyclooxygenase (COX) -1, -2 and lipoxygenase (LOX) protein expression. Moreover, the microdialysis study demonstrated that centrally injected nesfatin-1 increased the posterior hypothalamic extracellular AA products. In conclusion, these findings report that while nesfatin-1 is generating its autonomic effects, it also might be using central prostaglandins and leukotrienes by activating central COX and LOX pathways.

Nesfatin-1 Acts Centrally to Induce Sympathetic Activation of Brown Adipose Tissue and Non-Shivering Thermogenesis.

Nesfatin-1 has originally been established as a bioactive peptide interacting with key hypothalamic nuclei and neural circuitries in control of feeding behavior, while its effect on energy expenditure has only recently been investigated. Hence, the aim of this study was to examine whether centrally acting nesfatin-1 can induce ß3-adrenergic stimulation, which is a prerequisite for the activation of thermogenic genes and heat release from interscapular brown adipose tissue, key physiological features that underlie increased energy expenditure. This question was addressed in non-fasted mice stereotactically cannulated to receive nesfatin-1 intracerebroventricularly together with peripheral injection of the ß3-adrenoceptor antagonist SR 59230 A, to assess whole-body energy metabolism. Using a minimally invasive thermography technique, we now demonstrate that the thermogenic effect of an anorectic nesfatin-1 dose critically depends on ß3 adrenergic stimulation, as the co-administration with SR 59230 A completely abolished heat production from interscapular brown adipose tissue and rise in ocular surface temperature, thus preventing body weight loss. Moreover, through indirect calorimetry it could be shown that the anorectic concentration of nesfatin-1 augments overall caloric expenditure. Plausibly, central administration of nesfatin-1 also enhanced the expression of DIO2 and CIDEA mRNA in brown adipose tissue critically involved in the regulation of thermogenesis.

Centrally and peripherally injected nesfatin-1-evoked respiratory responses.

Nesfatin-1, which is an anorexiogenic peptide, plays a crucial role as a neurotransmitter and/or neuromodulator in the central nervous system for cardiovascular control and energy balance etc. It is expressed abundantly in multiple brain nuclei including central respiratory control areas such as nucleus tractus solitarius, nucleus ambiguous, dorsal vagal complex, dorsal motor nucleus of the vagus nerve, and hypothalamus. To date, no previous studies have been found to report nesfatin-1-evoked respiratory effects. Therefore, the present study was designed to investigate the possible impacts of centrally and/or peripherally injected nesfatin-1 on respiratory parameters in either 12h-fasted or fed-ad libitum rats. Intracerebroventricular (ICV) administration of nesfatin-1 provoked significant hyperventilation by increasing tidal volume (TV), respiratory rate (RR) and respiratory minute ventilation (RMV) in both the 12h-fasted and the fed-ad libitum Spraque Dawley rats in dose- and time- dependent manner. Moreover, the hyperventilatory effects of centrally injected nesfatin-1 were more potent in the fed-ad libitum rats. Intravenous injection of nesfatin-1 induced a significant rise in RR and RMV, but not in TV, in the fed-ad libitum rats. In conclusion, these findings plainly report that both centrally and/or peripherally injected nesfatin-1 induces significant hyperventilatory effects in the 12h-fasted and the fed-ad libitum rats. These hyperventilatory effects of nesfatin-1 might show a discrepancy according to the food intake of the rats and the delivery method of the peptide.

Nesfatin-1 protects from acute pancreatitis: role of melanocortin receptors.

Nesfatin-1, a recently discovered peptide, was shown to have anti-inflammatory effects. Acute pancreatitis (AP) is a life-threatening condition caused by various reasons. Although the etiology of AP is well-known, its pathogenesis is not clear. The aim of this study is to investigate the possible anti-inflammatory role of nesfatin-1 and its probable protective underlying mechanisms in an acute pancreatitis model. Caerulein was applied intraperitoneally to induce acute pancreatitis in Sprague-Dawley female rats. Nesfatin-1 was administered 5 minutes before the application of caerulein to determine its potential anti-inflammatory role on AP. Five minutes before nesfatin-1 injection, in order to investigate the underlying mechanism, oxytocin receptor antagonist (atosiban), melanocortin receptor antagonist (HS024), or ghrelin receptor antagonist (cortistatin) were administered. Five minutes after nesfatin-1 administration, two doses of caerulein were applied one hour apart. The rats were sacrified 12 hours after the first caerulein dose for serum and pancreatic tissue sampling. Microscopic damage scoring, malondialdehyde and glutathione levels, myeloperoxidase activity, luminol and lucigenin chemiluminescence levels in pancreatic tissue and amylase, lipase, trypsinogen-2 levels in serum were evaluated. Oxidative damage was decreased with nesfatin-1 treatment in the acute pancreatitis model (P < 0.05 - 0.001). The administration of HS024 reversed the effect of nesfatin-1, via increasing lipase, amylase, trypsinogen-2, malondialdehyde (MDA), myeloperoxidase (MPO) and lucigenin levels (P < 0.05 - 0.01). Atosiban pre-treatment elevated MPO activity, luminol and lucigenin chemiluminescence levels (P < 0.01 - 0.001) and cortistatin increased lucigenin and luminol chemiluminescence (P < 0.05 - 0.01). Although receptor antagonists reversed the effect of nesfatin-1 on related biochemical parameters, no significant difference was found in histological scoring. Our results indicated that nesfatin-1 had an anti-inflammatory effect on acute pancreatitis via mainly effecting melanocortin receptors.

Adropin, nesfatin-1 and angiotensin II receptor expression in the abdominal aorta in ovariectomized rats after nesfatin-1 treatment.

The aim of the research was to assess the effect of nesfatin-1 on the structure, flexibility parameters, and expression of adropin, nesfatin-1, and angiotensin II receptor type 1 (AT1R) in the abdominal aorta in ovariectomized rats. Fragments of aortas were collected after euthanasia of female sham-operated (CONT) and ovariectomized Wistar rats (EXP), which were administered intraperitoneal injection of physiological saline (CONT, n = 7; EXP-O, n = 7) or nesfatin-1 (EXP-N, n = 7) in an amount of 2 µg/kg b.w. once a day for 8 weeks. The samples of aortas were collected for measurement of elasticity as well as histomorphometric, immunohistochemical, FTIR, and Raman spectroscopy analysis. The ovariectomy caused a significant increase in the thickness of the total wall and its particular layers in the aorta, in comparison to the CONT and EXP-N groups. However, the ovariectomy led to a decrease in the amount of elastin, collagen (mature, immature collagen, collagen maturity ratio 1660 - 1690 cm-1), and amides, with a simultaneous increase in lipids, especially in the tunica intima-media of the abdominal aorta compared to the other groups. The use of nesfatin-1 significantly increased the amount of collagen, elastin and amides with a simultaneous decrease in the amount of lipids and the expression of AT1R, adropin and nesfatin-1 in the abdominal aorta of ovariectomized rats. In conclusion, our study showed that the ovariectomy surgery induced changes in the abdominal aorta wall characteristic for aging females. Application of nesfatin-1 may prevent the negative consequences in the vessel wall structure in females in conditions of estrogen deficiency and prevent atherosclerotic changes in the cardiovascular system.