Kouichi Sashihara

Intracerebroventricular injection of fusaric acid attenuates the anorexia by glucagon-like peptide-1 in the neonatal chick

It is known that central injection of glucagon-like peptide-1 (GLP-1) suppresses feeding in rats and chicks, but the systems for GLP-1 are still open with special reference to the chick. The present study was done to determine whether a noradrenergic mechanism contributes to the anorexigenic effect of GLP-1 on the neonatal chick. Central administration of norepinephrine (NE) suppressed food intake with narcolepsy as GLP-1 in chicks. However, in spite of that dopamine (DA) did not affect food intake, coadministration of inhibitor of dopamine-beta-hydroxylase (DBH), fusaric acid (FA), attenuated the suppressive effect of GLP-1 on feeding behavior. It is suggested that there may be the interactive relationships between GLP-1 and noradrenergic system in the neonatal chick.

Intracerebroventricular injection of exendin (5–39) increases food intake of layer-type chicks but not broiler chicks

To clarify the involvement of endogenous glucagon-like peptide-1 (GLP-1) on feeding in chicks, we examined the central effect of GLP-1 antagonist, exendin (5-39) on food intake. Intracerebroventricular co-injection of exendin (5-39) with GLP-1 attenuated the anorexigenic effect of GLP-1 in layer-type chicks. Furthermore, exendin (5-39) enhanced food intake of layer-type chicks under ad libitum feeding. However, this effect was not observed in broiler chicks. Therefore, endogenous GLP-1 may be important in the regulation of feeding in layer-type chicks but not in broiler chicks.

Ghrelin Activates Behavior of Neonatal Chicks in a Short Period of Post-Intracerebroventricular Injection

Abstract Saito, E., Takagi, T., Nakanishi, T., Sashihara, K. and Furuse, M. 2002. Ghrelin activates behavior of neonatal chicks in a short period of post-intracerebroventricular injection. J. Appl. Anim. Res., 22: 33–41. Ghrelin, a novel growth hormone (GH)-releasing peptide with an acylated side chain, is the endogenous ligand for the GH secretagogue receptor. Intracerebroventricular (ICV) injection of ghrelin stimulates GH secretion and feeding of rats, but ghrelin inhibited feeding of neonatal chicks. It was also confirmed that ghrelin induced sleep-like behavior later than 30 minutes post-administration in neonatal chicks. However, exciting behavior was observed in a short period (less than 30 min) in previous reports. Thus, we further investigated the behavioral changes in neonatal chicks by ICV administration of ghrelin within a short period. Chicks were divided into two groups and administered ICV saline or 2μg of ghrelin and the numbers of step and vocalization were monitored. Just after behavioral test, the amount of monoamines of chick hypothalamus was determined by high performance liquid chromatography. Central ghrelin enhanced the numbers of step and kept the numbers of vocalization, but no significant difference in the amount of monoamines was detected. In conclusion, central ghrelin activates chick behavior in a short period without modification of hypothalamic monoamine contents.

Effect of Orally Administered Conjugated Linoleic Acids on Behaviors and Tissue Fatty Acid Compositions in Mice

Abstract Nakanishi, T., Ohgushi, A., Yamashita, T., Sashihara, K., Takagi, T., Dobashi, E., Kamegai, T., Kasai, M., Yoshimatsu, T. and Furuse, M. 2001. Effect of orally administered conjugated linoleic acids on behaviors and tissue fatty acid compositions in mice. J. Appl. Anim. Res., 20: 157–170. To compare the influences of the oral administration of conjugated linoleic acids (CLA) on behaviors and fatty acid composition of some tissues with those of linoleic acid, (LA) and docosahexaenoic acid (DHA), mice (8-week old) were orally administered with oils containing high levels of CLA DHA or LA for 4 weeks (6 days per week, 0.2 ml per day). Control, group was administered with saline. Behavioral tests such as locomotor activity swim test elevated plus maze lest and biting test, were done on the commencement of the study (0 week) and 2 and 4 weeks after treatments. No significant changes were observed in, all the parameters. Oral. CLA increased the liver weight and reduced the epididymal, white adipose tissue weight. The ratio of arachidonic acid to total, fatty acids was significantly increased by LA and decreased, by CLA compared with the control, especially in the liver. Small amounts of CLA were detected in the brain of mice administered with CLA or LA groups, but, not detected, in mice of the control and DHA groups. The level of DHA in the brain was not altered by DHA administration. It is concluded that oral administration of CLA influenced some tissues but not behaviours of mice at least after growth.

Role of Central Serotonergic Systems on the Regulation of Feeding Behavior of Chicks in Two Different Strains

Abstract Sashihara, K., Bungo, T., Ando, R., Ohgushi, A., Kawakami, S.-I., Denbow, D.M. and Furuse, M. 2002. Role of central serotonergic systems on the regulation of feeding behavior of chicks in two different strains. J. Appl. Anim. Res., 21: 17–23. Significant role of 5-HT for control of feeding behavior in mammalian and avian species is well known. To study the strain difference in the mechanisms of serotonergic systems on food intake, effects of intracerebroventricular (ICV) injection of serotonin (5-HT) or 8-hydroxy-2-di-n-(propylamino) tetralin (8-OH-DPAT: 5-HT1A receptor agonist) on two strains of chicks (Cobb and Ross Chunky) was examined. Central administration of 5-HT suppressed food intake of chicks in both strains, but 5-HT induced anorexia lasted longer in Cobb than in Ross Chunky. Food intake in Ross Chunky enhanced by the highest dose of 8-OH-DPAT, but not in Cobb. The difference of sensitivity for 5-HT between two strains could be because of the density or binding affinity of 5-HT1A receptor. This evidence suggests that there are some genetic differences in central serotonergic systems between two strains on the regulation of food intake.

Influence of ketone body and the inhibition of fatty acid oxidation on the food intake of the chick

1. Fatty acid oxidation is known to be involved in the control of food intake in mammals. The effect of fatty acid oxidation on food intake in chickens was studied using a ketone body ( β -hydroxybutyrate ( β -HB)) and mercaptoacetate (MA) (an inhibitor of fatty acid oxidation). 2. Central and peripheral injection of β -HB decreased food intake in a dose-dependent manner, while low doses of MA had no effect. Higher doses of MA inhibited feeding but also caused mortality. 3. These results indicate that ketone bodies act as an inhibitory signal for food intake in both the central and peripheral nervous systems but that inhibition of fatty acid oxidation may not be associated with feeding behaviour in chicks.

Effect of Environmental Lighting on Aggressive and Anxious Behavior in Male Mice

Abstract Koutoku, T., Nakanishi, T., Takagi, T., Yamasaki, I., Zhang, R., Sashihara, K., Saito, E.-S., Saito, S. and Furuse, M. 2003. Effect of environmental lighting on aggressive and anxious behavior in male mice. J. Appl. Anim. Res., 23: 65–74. To study the influence of the different conditions of environmental lightning on aggressive behavior and open field activity, male mice were kept under different conditions of environmental lighting, i.e., A) 12-hour each light and dark (LD), B) continuous light (LL) and C) continuous dark (DD) for 27 days. Although no significant differences were observed among three groups, LL and DD conditions tended to show the inhibitory effect on aggression. In the open field test, the crossing, the time and the path significantly increased with the length of lighting period, but the rearing and defecation were not affected. The amounts of monoamines and their metabolites in the cerebellum, cerebrum and brainstem were hardly affected by lighting conditions. Taken together, DD condition was most preferable for mice to keep calm rather LL condition.

Feeding and Drinking Responses and Hypothalamic Monoamine Concentrations of Neonatal Chicks Following Intracerebroventricular Injection of 6-OHDA

Abstract Bungo, T., Tachibana, T., Sashihara, K., Kawakami, S.-I., Ohgushi A., Furuse, M. and Ueda, H. 2002. Feeding and drinking responses and hypothalamic monoamine concentrations of neonatal chicks following intracerebroventricular injection of 6-OHDA. J. Appl. Anim. Res., 22: 183–192. To clarify the involvement of catecholaminergic systems in the regulation of food and water intake in the neonatal chick, 6-hydroxydopamine (6-OHDA) or fusaric acid (FA) was administered intracerebroventricularly ICV) and the concentrations of monoamine in the hypothalamus were determined. We found that food intake was significantly increased by ICV injection of 6-OHDA (25, 50 and 100 μg) until 60 min after injection, but the effect disappeared at 120 min. Although both 6-OHDA and FA had no significant effect on water intake, the water consumption in chicks treated with FA tended to be higher than that with saline (control). Norepinephrine (NE) in the hypothalamus was reduced in chicks treated with 6-OHDA (P<0.05). These results indicate that changes in NE concentration of the hypothalamus mainly influence food intake in chicks.