Biomedical subjects

Mitsuhiro Furuse

Publications and source records attributed to Mitsuhiro Furuse.

At least 19 recordsLinked to original sources

PubMed2006

Central ghrelin acts as an anti-dipsogenic peptide in chicks.

The aim of this study was to look at whether ghrelin has an anti-dipsogenic effect, as seen in the eel, when administered centrally in neonatal chicks. Intracerebroventricular (ICV) injection of chicken ghrelin inhibited water intake (WI) in chicks under both ad libitum and 17-h water-deprived drinking conditions at doses ranging from 0.01 to 0.1nmol/chick. This inhibitory effect was observed when 0.1nmol of rat ghrelin was injected. On the other hand, 0.1nmol des-acyl rat ghrelin did not reduce WI. To examine the mechanism underlying the effect of ghrelin on WI, chicken B-type (or brain) natriuretic peptide (BNP), an anti-dipsogenic peptide in mammals, was injected at doses ranging from 0.1 to 1nmol/chick. BNP did not affect WI in chicks under both normal and water-deprived drinking conditions. These findings indicate that ghrelin acts as an anti-dipsogenic peptide through the GHS receptor in the chicken.

Analysis of Variance↗

PubMed2006

Intracerebroventricular injection of neuropeptide Y modifies carbohydrate and lipid metabolism in chicks.

The purpose of the present study was to investigate whether intracerebroventricular (ICV) injection of neuropeptide Y (NPY) affects heat production (HP), body temperature, and plasma concentrations of metabolic fuels in chicks. ICV injection of NPY (0, 188 or 375 pmol) did not affect HP, but significantly lowered respiratory quotient as well as the rectal temperature. These data suggest that the energy sources for HP were modified by NPY in the body. This idea was confirmed by subsequent experiments in which ICV injection of NPY significantly reduced plasma glucose and triacylglycerol concentrations but increased non-esterified fatty acid concentrations. The effect of NPY on the utilization of metabolic fuels was not associated changes in plasma catecholamine and corticosterone concentrations. In summary, the present study demonstrated that central NPY modifies peripheral carbohydrate and lipid metabolism in chicks.

Animals↗

PubMed2006

Thyrotropin-releasing hormone increased heat production without the involvement of corticotropin-releasing factor in neonatal chicks.

Thyrotropin-releasing hormone (TRH) is a hypothalamic signal in the hypothalamic-pituitary-thyroid (HPT) axis, and is well known as a hyperthermic hormone in the brain of chicks. The thermogenetic effect leads to the hypothesis that central TRH increases heat production (HP) in chicks. The purpose of the present study was to clarify whether central TRH affects HP of neonatal chicks, and if such an effect is mediated by corticotropin-releasing factor (CRF) since the thermogenetic effect of TRH is mediated by CRF. Intracerebroventricular (ICV) injection of TRH (14 and 55 nmol) dose-dependently increased oxygen consumption, carbon dioxide production and HP, and a similar effect was also observed with CRF (2.1 and 21 pmol). The TRH-induced increase in HP could not be attenuated by astressin, a CRF receptor antagonist, while the effect of CRF was completely diminished by astressin. The present study demonstrates that central TRH increases HP in chicks but the effect was not related to CRF.

Animals↗

PubMed2006

Changes in ghrelin levels of plasma and proventriculus and ghrelin mRNA of proventriculus in fasted and refed layer chicks.

This is a test-report of ghrelin levels in plasma and proventriculus, the glandular portion of the avian stomach, by using a specific radioimmunoassay for acylated ghrelin, as well as the expression of the ghrelin gene in the proventriculus after a 12-h fasting period followed by a 6-h feeding period with 6-day-old layer chicks. After fasting, the plasma ghrelin levels increased from 21.3+/-4.5 to 32.9+/-5.0 fmol/ml, but once refed it returned to the control value. After fasting, the ghrelin mRNA and the peptide levels in the proventriculus increased, and ghrelin mRNA levels remained high but once refed the ghrelin content returned to the control level. Furthermore, in order to examine the effect of increased circulating ghrelin on food intake, a bolus intravenous injection of 500 pmol of chicken ghrelin was given to 8-day-old chicks. The ghrelin injection did not cause any significant changes in food intake. These results indicate that the levels of ghrelin and its mRNA with layer chicks are altered according to the feeding state and this in a similar manner as has been observed in mammals. Unlike in mammals, an increase in circulating ghrelin does not cause the promotion of food intake in chicks.

Analysis of Variance↗

PubMed2006

Intracerebroventricular injection of L-serine analogs and derivatives induces sedative and hypnotic effects under an acute stressful condition in neonatal chicks.

Four experiments were conducted to clarify the central functions of L-serine and its analogs on an acute stressful condition. Intracerebroventricular (i.c.v.) injection of L-serine (0.21, 0.42 and 0.84 micromol) attenuated stress responses in a dose-dependent fashion, as well as induced sleep, in Experiment 1. The effects of L- and D-serine in Experiment 2, those of L-serine, phosphoserine, acetylserine and L-cysteine in Experiment 3 and those of L-serine, glycine and lysophosphatidylserine in Experiment 4 were compared at an equimolar basis (0.84 micromol). D-Serine, proposed as an endogenous agonist of N-methyl-D-aspatate (NMDA) receptor, did not have sedative and hypnotic effects as observed with L-serine. In contrast, all the analogs and derivatives of L-serine had a sedative effect, although with a different manner in several behavioral markers of stress such as spontaneous activity and distress vocalizations. No significant changes in plasma corticosterone concentration were observed in any experiment. Taken together, the i.c.v. injection of L-serine analogs and its derivatives have sedative and hypnotic effects under an acute stressful condition, which does not involve the hypothalamic-pituitary-adrenal axis. In conclusion, L-serine may be effective in improving anxiety or sleep disorders induced by psychological stressor.

Age Factors↗

PubMed2006

Heat production and lipid metabolism in broiler and layer chickens during embryonic development.

We compared heat production (HP) and lipid metabolism in broiler and layer chickens (Gallus gallus) during embryonic development. To investigate HP and respiratory quotient (RQ), oxygen (O2) consumption and carbon dioxide (CO2) production were measured using an open-circuit calorimeter system. HP consistently had a tendency (P = 0.06) to be lower in broilers than in layers during embryonic development, and HP gradually decreased with developmental stage in both strains. RQ values of both strains were approximately 0.7 at every embryonic stage investigated. These results suggest that chicken embryos mainly use lipid for energy, and the RQ was significantly lower in broilers than in layers during embryonic development. Consumption of the yolk sac as a lipid source was faster in broilers than in layers. Plasma D-3-hydroxybutyrate (D3HB) and glycerol concentrations, associated with fatty acid oxidation, were lower in broiler than layer embryos. These results demonstrate that HP and lipid metabolism are different between the strains during embryonic development, and may be one factor for the growth difference between broiler and layer embryos.

3-Hydroxybutyric Acid↗

PubMed2006

(-)-Epigallocatechin gallate attenuates acute stress responses through GABAergic system in the brain.

(-)-Epigallocatechin gallate (EGCG), a flavonoid, is the principal catechin found in green tea and is distributed in the brain after tea consumption. The aim of the present study was to investigate the effects of EGCG in the chick brain under an acute stressful condition and to clarify the mechanism by which EGCG attenuates stress behavior with special reference to gamma-aminobutyric acid (GABA). Intracerebroventricular (i.c.v.) injection of EGCG (50, 100 and 200 microg) suppressed the vocalization which normally occurs during social separation stress. EGCG decreased the time spent in active wakefulness and induced sleep-like behavior in a dose-dependent manner. Additionally, i.c.v. injection of EGCG attenuated plasma corticosterone release under social separation stress. These effects of EGCG on distress-induced vocalization were significantly attenuated by the GABAA receptor antagonist picrotoxin but not by the GABAB receptor antagonist CGP 54626 (3-N-(1-(3,4-dichlorophenyl)ethylamino)-2-hydroxypropyl cyclohexylmethyl phosphinic acid hydrochloride). These results indicate that EGCG has sedative and hypnotic effects in the brain, partially through GABAA receptors, and consequently moderates an acute stress response.

Animals↗

PubMed2005

Involvement of CRF on the anorexic effect of GLP-1 in layer chicks.

Glucagon-like peptide-1 (GLP-1) is recognized as an anorexic peptide in the brain of chicks. However, the mechanism underlying the inhibition of feeding has not been well studied. It is reported that GLP-1 activates neurons containing corticotrophin-releasing factor (CRF) in the brain of mammals. Since CRF is also an anorexic peptide, it is possible that the anorexic effect of GLP-1 is mediated by CRF in chicks. The present study was carried out to test this. First, we determined plasma corticosterone (CORT) concentrations after intracerebroventricular (ICV) injection of GLP-1 and found that this treatment increased CORT release in layer chicks. The CORT-releasing effect was partly attenuated by co-injection of astressin, a CRF receptor antagonist, demonstrating that GLP-1 stimulated CORT secretion by activation of CRF neurons. CRF neurons also appear to be involved in mediating the inhibition of food intake by GLP-1 because this effect was also partly attenuated by astressin. Furthermore, we demonstrated that the anorexic effect of GLP-1 was weaker in broiler than layer chicks. The present results suggest that the anorexic effect of GLP-1 might be mediated by CRF neurons in the chick brain and that the sensitivity of the inhibitory response to GLP-1 differs between chick strains.

Animals↗

PubMed2005

Nitric oxide involves in carnosine-induced hyperactivity in chicks.

Carnosine has been characterized as a putative neurotransmitter and implicated as having a possible role in neuron-glia cell interactions. We previously confirmed that central administration of carnosine induced hyperactivity in chicks. In the present study, we investigated the effects of nitric oxide (NO) synthase (NOS) inhibitors on carnosine-induced hyperactivity in chicks. Carnosine-induced (3.2 micromol) hyperactivity was attenuated by intracerebroventricular (i.c.v.) co-administration with a non-selective NOS inhibitor N(G)-nitro-L-arginine methyl ester HCl (200 and 400 nmol) in a dose-dependent manner, while the hyperactivity was not attenuated by the inactive isomer of the NOS inhibitor N(G)-nitro-D-arginine methyl ester HCl (400 nmol). The i.c.v. injection of a selective inhibitor of inducible NOS (iNOS) L-N(6)-(1-iminoethyl) lysine HCl (400 nmol) did not affect carnosine-induced hyperactivity. These results suggest that carnosine-induced hyperactivity may be linked to the constitutive NOS (cNOS), rather than iNOS, in the brain. Central carnosine may regulate brain function and/or behaviors by NO generation via cNOS in chicks.

Animals↗

PubMed2005

ICV melatonin reduces acute stress responses in neonatal chicks.

Melatonin is involved in a variety of biological functions including sleep and stress. Our previous study indicated that neonatal layer chicks were more susceptible to stress than broilers. However, it is not clear whether differences exist in melatonin concentrations between both types of chickens, nor is it known whether melatonin is directly involved in stress in neonatal chickens. In the present study we first compared melatonin concentrations in brain tissues (pineal gland, brain stem, telencephalon, and optic lobe) between neonatal broiler and layer chicks raised under either 12 h light:12 h dark cycle (lights on at 07:00 h) or continuous illumination. Although melatonin concentrations were much higher in broilers than layers at night under the alternative light-dark cycle, these differences disappeared under the 24 h illumination. We thus chose neonatal layers for a test system. We then investigated if intracerebroventricular (ICV) injection of melatonin modulated plasma corticosterone concentrations under continuous illumination. Neonatal layer chicks housed in groups were ICV injected (1) with melatonin (0, 0.116 and 1.16 microg) or with nothing as an intact control followed by isolation in an open-field environment for 10 min; and (2) were given one of the followings treatments: nothing (intact control), control (0 microg), corticotropin-releasing factor (CRF) (0.01 microg), melatonin (1.16 microg), or CRF (0.01 microg) + melatonin (1.16 microg). Ten minutes thereafter blood was collected via heart puncture to determine plasma corticosterone content. Isolation resulted in a significant increase in corticosterone concentration, and both doses of ICV melatonin completely suppressed this increase (P<0.01). CRF injection resulted in a strong increase in plasma corticosterone concentrations (P<0.01). Co-injection with melatonin attenuated the CRF-induced corticosterone elevation in plasma (P<0.01). Our findings provide direct evidence that melatonin modulates the activity of the hypothalamo-pituitary-adrenal axis in chicks.

Analysis of Variance↗

PubMed2005

Comparison of mammalian prolactin-releasing peptide and Carassius RFamide for feeding behavior and prolactin secretion in chicks.

Prolactin-releasing peptide (PrRP) was named for its originally reported effects as a prolactin (PRL) secretagogue in mammals. Carassius RFamide (C-RFa) is an orthologous PRL secretagogue in fishes and a gene encoding a 20-amino acid peptide of identical sequence is present in the chicken. These facts suggest that C-RFa is a putative chicken PrRP. However, no information is available for the physiological effects of C-RFa in chickens. Therefore, in the present study, we compared the effect of intracerebroventricular (ICV) injection of C-RFa and mammalian PrRP (mPrRP) on feeding behavior and plasma PRL, growth hormone (GH), and corticosterone (CORT) concentrations. ICV injection of C-RFa did not affect feeding behavior of chicks while mPrRP was stimulatory. The injection of C-RFa also did not significantly affect plasma PRL, GH, and CORT concentrations. In contrast, ICV injection of mPrRP exerted similar effects to those reported in mammals by increasing plasma CORT and decreasing GH concentrations. Additionally, the peptide induced an unexpected inhibitory effect on plasma PRL concentrations. Overall, these data suggest that an as yet unidentified peptide that shares some functional similarities with mPrRP is present in birds, but that the physiological role of the avian 20-amino acid C-RFa peptide remains to be determined.

Animals↗

PubMed2005

Gonadotropin-inhibiting hormone stimulates feeding behavior in chicks.

Neuropeptides containing a C-terminal Arg-Phe-NH2 motif (RFamide peptides) are suggested to be involved in the control of feeding behavior in both invertebrates and vertebrates. Gonadotropin-inhibitory hormone (GnIH) is the first identified avian RFamide peptide that inhibits gonadotropin release from the pituitary. The GnIH precursor encodes one GnIH and its related peptides (GnIH-RP-1 and -RP-2) that shared the same C-terminal motif, Leu-Pro-Xaa-Arg-Phe-NH2 (Xaa = Leu or Gln) (LPXRFamide). GnIH neurons are localized in the paraventricular nucleus, with their fibers visible in multiple brain locations including the median eminence and brainstem. In this study, we therefore investigated the action of GnIH and its related peptides on feeding behavior. Intracerebroventricular (ICV) injection of GnIH, GnIH-RP-1 and GnIH-RP-2 significantly stimulated food intake in chicks. The chicken pentapeptide LPLRFamide, a degraded C-terminus of GnIH and GnIH-RP-1, did not stimulate feeding thereby demonstrating the importance of the N-terminus of GnIH and its related peptides for the orexigenic effect. Anti-GnIH antiserum suppressed appetite induced by fasting, but did not modify feeding under ad libitum conditions. The present study suggests that GnIH and its related peptides act as endogenous orexigenic factors in the brain of chicks.

Amino Acid Sequence↗

PubMed2005

Regulation of body temperature by thyrotropin-releasing hormone in neonatal chicks.

To understand thermal regulation of neonatal chicks, the contribution of thyrotropin-releasing hormone (TRH), a key regulator of the hypothalamus-pituitary-thyroid axis, was investigated. Intracerebroventricular (i.c.v.) injection of TRH (5 and 20 microg) increased body temperature, but did not change plasma T3 and T4 concentrations. Intraperitoneal (i.p.) injection of triiodothyronine (T3) and thyroxine (T4) did not influence body temperature. Thereafter, the relationships between TRH and the hypothalamus-pituitary-adrenal axis and sympathetic nervous system were further investigated. Central TRH stimulated both corticosterone and epinephrine release. The i.c.v. injection of a corticotropin-releasing factor receptor antagonist attenuated the change in body temperature and corticosterone concentration caused by TRH, but did not influence plasma T3 and T4 concentrations. The i.p. injection of epinephrine did not induce hyperthermia. Therefore, the thermoregulatory response to TRH may differ in neonatal stages being dependent upon the stimulation of the hypothalamus-pituitary-adrenal axis rather than the hypothalamus-pituitary-thyroid axis.

Animals↗

PubMed2005

Inhibitory effect of ghrelin on food intake is mediated by the corticotropin-releasing factor system in neonatal chicks.

It is known that, in rats, central and peripheral ghrelin increases food intake mainly through activation of neuropeptide Y (NPY) neurons. In contrast, intracerebroventricular (ICV) injection of ghrelin inhibits food intake in neonatal chicks. We examined the mechanism governing this inhibitory effect in chicks. The ICV injection of ghrelin or corticotropin-releasing factor (CRF), which also inhibits feeding and causes hyperactivity in chicks. Thus, we examined the interaction of ghrelin with CRF and the hypothalamo-pituitary-adrenal (HPA) axis. The ICV injection of ghrelin increased plasma corticosterone levels in a dose-dependent or a time-dependent manner. Co-injection of a CRF receptor antagonist, astressin, attenuated ghrelin-induced plasma corticosterone increase and anorexia. In addition, we also investigated the effect of ghrelin on NPY-induced food intake and on expression of hypothalamic NPY mRNA. Co-injection of ghrelin with NPY inhibited NPY-induced increase in food intake, and the ICV injection of ghrelin did not change NPY mRNA expression. These results indicate that central ghrelin does not interact with NPY as seen in rodents, but instead inhibits food intake by interacting with the endogenous CRF and its receptor.

Animals↗

PubMed2005

Dietary Garcinia cambogia does not modify skin properties of mice with or without excessive sucrose intake.

The influence of 3.3% Garcinia cambogia extract on the properties of mouse skin with or without 10% sucrose water loading was investigated. Mice (7-week-old) were given free access to a control diet or a diet containing Garcinia cambogia extract. They were also given water alone or both water and sucrose water. Their skin was compared by both biochemical and histological methods. The collagen and triacylglycerol contents were not significantly different among the four groups. Similarly, electron microscopy revealed no differences in the thickness of the dermis layer or the subcutaneous tissue layer. Mice given the diet containing Garcinia cambogia tended to have a reduced total number of adipocytes, but not significantly. These results suggest that Garcinia cambogia supplementation for at least 4 weeks does not induce a negative effect on skin properties in mice irrespective of excessive sucrose intake.

Administration, Oral↗

PubMed2005

Distribution of proglucagon mRNA and GLP-1 in the brainstem of chicks.

Glucagon-like peptide-1 (GLP-1), structurally similar to glucagon, synthesized from the precursor proglucagon, is a well known anorexigenic peptide in the brain of several animal species. However, there are no previous reports concerning GLP-1-containing neurons in the chick brain. The aim of the present study was to investigate the distribution of proglucagon mRNA and GLP-1-immunoreactive (GLI) perikarya in various regions of the chick brain. We detected proglucagon mRNA in the brainstem, and to a lesser extent in the telencephalon. In the brainstem, a study using immunohistochemistry revealed that GLI perikarya were present in the nucleus motorius nervi facialis pars dosalis, nucleus motoris dorsalis nervi vagi and nucleus tractus solitarii. Furthermore, we found that proglucagon mRNA expression in the brainstem decreased after 24 h fasting. The present findings support the idea that endogenous GLP-1 is involved in feeding behavior of chicks.

Animals↗

PubMed2005

ICV CRF and isolation stress differentially enhance plasma corticosterone concentrations in layer- and meat-type neonatal chicks.

The present study compared the plasma corticosterone concentrations between meat- and layer-type neonatal chicks (Gallus gallus) (1) exposed to isolation-induced stress or (2) injected intracerebroventricularly (ICV) with corticotropin-releasing factor (CRF). Both types of neonatal chicks housed in groups were individually introduced to an open field arena and locomotion and distress-induced vocalizations were monitored for 10 min. The responses of the two strains were remarkably different, with meat-type chicks being less active than layer-type chicks. Distress-induced vocalizations were drastically decreased over time in meat-type chicks while they remained high in layer-type chicks throughout the test. Plasma corticosterone concentrations measured at the end of the test were significantly higher in layer-type chicks than in meat-type ones. Plasma corticosterone concentrations measured 10 min after the ICV injection of CRF were significantly higher in layer- than meat-type chicks. These results indicate that meat-type chicks have either a greater capability to acclimatize to novel environments, or a blunted HPA axis compared with layer-type chicks.

Animals↗

PubMed2005

Central administration of phosphatidylserine attenuates isolation stress-induced behavior in chicks.

The present study investigated whether centrally administered phosphatidylserine (PS) could modify the behavior of chicks under isolation-induced stress. Isolation stress-induced vocalization and spontaneous activity for 10 min, which were attenuated by intracerebroventricular (i.c.v.) injection of PS. The effect of PS was compared with other phospholipids or L-serine, a constituent of PS. Phosphatidylcholine (PC) had no effect on these behavior, but phosphatidylethanolamine (PE) significantly increased vocalizations and spontaneous activity compared with PS. L-Serine similarly decreased isolation-induced vocalizations and spontaneous activity. To clarify the mechanism by which central PS attenuates isolation-induced stress behavior, the contribution of the acetylcholine (ACh) receptor (AChR) was also investigated. PS was co-injected i.c.v. with the muscarinic AChR (M-AChR) antagonist scopolamine or the nicotinic AChR (N-AChR) antagonist hexamethonium. The suppression of vocalizations and spontaneous activity by PS was partially attenuated by scopolamine, but not hexamethonium. These findings indicate that isolation-induced stress behavior are attenuated by PS, acting partially through the M-AChR.

Animals↗