Effects of essence of chicken on cognitive brain function: a near-infrared spectroscopy study.

The aim of this study was to investigate the effects of the essence of chicken on brain function by near-infrared spectroscopy. Twelve healthy elderly subjects took the essence of chicken or a placebo for 7 d in a double-blind cross-over design study. Changes in oxy-hemoglobin concentrations in the bilateral prefrontal areas of the brain were measured while the subjects performed the simple reaction task, the Groton Maze Learning Test, and the working memory task. In the latter case, there were significant interactions in the changes in oxy-hemoglobin concentrations between treatment and period of intake according to two-way repeated ANOVA. The changes in oxy-hemoglobin concentrations significantly increased in several regions of the prefrontal areas of the brain in those taking essence of chicken for 7 d. These results suggest that essence of chicken is useful as a nutritional supplement to enhance or maintain brain function in the elderly.

Effects of chicken essence on recovery from mental fatigue in healthy males.

BACKGROUND: Fatigue is a common symptom in modern society. There has been a recent resurgence of interest in traditional remedies for fatigue. Chicken essence, which is rich in anserine and carnosine, has been widely taken in Asian countries as a traditional remedy with various aims, including attenuation of physical and mental fatigue. However, the evidence for its efficacy specifically for mental fatigue remains unclear. We examined the effect of essence of chicken on mental fatigue in humans, using our established fatigue-inducing task and evaluation methods. MATERIAL AND METHODS: In this placebo-controlled crossover study, 20 healthy male volunteers were randomized to receive daily oral administration of essence of chicken or placebo drink provided by Cerebos Pacific Ltd. via Suntory holdings Ltd. for 4 weeks. The participants performed 2-back test trials as a fatigue-inducing mental task and then had a rest session. Just before and after each session, they completed cognitive task trials focusing on selective attention to evaluate the level of mental fatigue. RESULTS: After essence of chicken intake for 1 and 4 weeks, the reaction times on the cognitive task trials after the rest session were significantly shorter than those at baseline, and significant changes were not observed with placebo intake. The reaction times before and after the fatigue-inducing session were not altered by either essence of chicken or placebo intake. CONCLUSIONS: We showed that daily intake of essence of chicken could be effective for the recovery from mental fatigue and is a promising candidate for use as an anti-fatigue food.

Role of L-carnosine in the control of blood glucose, blood pressure, thermogenesis, and lipolysis by autonomic nerves in rats: involvement of the circadian clock and histamine.

L-carnosine (ß-alanyl-L-histidine; CAR) is synthesized in mammalian skeletal muscle. Although the physiological roles of CAR have not yet been clarified, there is evidence that the release of CAR from skeletal muscle during physical exercise affects autonomic neurotransmission and physiological functions. In particular, CAR affects the activity of sympathetic and parasympathetic nerves innervating the adrenal glands, liver, kidney, pancreas, stomach, and white and brown adipose tissues, thereby causing changes in blood pressure, blood glucose, appetite, lipolysis, and thermogenesis. CAR-mediated changes in neurotransmission and physiological functions were eliminated by histamine H1 or H3 receptor antagonists (diphenhydramine or thioperamide) and bilateral lesions of the hypothalamic suprachiasmatic nucleus (SCN), a master circadian clock. Moreover, a carnosine-degrading enzyme (carnosinase 2) was shown to be localized to histamine neurons in the hypothalamic tuberomammillary nucleus (TMN). Thus, CAR released from skeletal muscle during exercise may be transported into TMN-histamine neurons and hydrolyzed. The resulting L-histidine may subsequently be converted into histamine, which could be responsible for the effects of CAR on neurotransmission and physiological function. Thus, CAR appears to influence hypoglycemic, hypotensive, and lipolytic activity through regulation of autonomic nerves and with the involvement of the SCN and histamine. These findings are reviewed and discussed in the context of other recent reports, including those on carnosine synthetases, carnosinases, and carnosine transport.

Polyphenols in alcoholic beverages activating constitutive androstane receptor CAR.

The constitutive androstane receptor CAR is a xenosensing nuclear receptor that can be activated by natural polyphenols such as flavonoids and catechins. We examined alcoholic beverage phytochemicals for their ability to activate CAR. HepG2 cells were transfected with CAR expression vector and its reporter gene, and then treated with trans-resveratrol, ellagic acid, ß-caryophyllene, myrcene, and xanthohumol. A luciferase assay revealed that ellagic acid and trans-resveratrol activated both human and mouse CAR. Since CAR regulates many genes involved in energy metabolism, the possibility exists that these polyphenols would reduce the risk of certain alcohol-induced metabolic disorders with the help of CAR.

Effects of flavangenol on autonomic nerve activities and dietary body weight gain in rats.

In a previous report, evidence was presented that flavangenol supplementation has an anti-ischemic effects in rats. In the study presented here, we examined the autonomic effects of intraduodenal (ID) injection of flavangenol in urethane-anesthetized rats and found that it increased sympathetic nerve activity innervating brown adipose tissue (BAT-SNA) in a dose-dependent manner, while it suppressed gastric vagal nerve activity (GVNA). In addition, intra-oral (IO) injection of flavangenol elevated brown adipose tissue temperature (BAT-T). Furthermore, flavangenol drinking for 15 d reduced body weight gain in rats fed a high-fat diet. These results thus suggest that flavangenol supplementation exerts its reducing action on body weight through changes in autonomic neurotransmission.

Effects of oolong tea on renal sympathetic nerve activity and spontaneous hypertension in rats.

In a previous study, evidence was presented that oolong tea (OT) reduced abdominal fat accumulation in diet-induced obese mice. In the study presented here, we examined the sympathetic and cardiovascular effects of intraduodenal injection of OT in urethane-anesthetized rats and found that it suppressed renal sympathetic nerve activity (RSNA) and blood pressure (BP). In addition, pretreatment with the histaminergic H3-receptor antagonist thioperamide or bilateral subdiaphragmatic vagotomy eliminated the effects of OT on RSNA and BP. Furthermore, OT drinking for 14 weeks reduced BP elevation in spontaneously hypertensive rats. These results thus suggest that OT may exert its hypotensive action through changes in autonomic neurotransmission via an afferent neural mechanism. Moreover, we found that intraduodenal injection of decaffeinated OT lowered RSNA and BP as well as OT, indicating that substances other than caffeine contained in OT may function as effective modulators of RSNA and BP.

Effects of central injection of L-carnosine on sympathetic nerve activity innervating brown adipose tissue and body temperature in rats.

In the present study, using urethane-anesthetized rats, we examined the effects of intralateral cerebral ventricular (LCV) injection of various doses of L-carnosine on neural activity innervating brown adipose tissue (BAT-SNA) and body temperature (BT). We found that injection of a low dose of L-carnosine (0.01 microg) suppressed BAT-SNA significantly. Conversely, a high dose (100 microg) of L-carnosine significantly elevated BAT-SNA. In the light period (14:00), brown adipose tissue temperature (BAT-T) and BT were suppressed after low and elevated after high dose injection of L-carnosine whereas in the dark period (2:00), these parameters remained unchanged with L-carnosine treatment. Bilateral lesions of the hypothalamic suprachiasmatic nucleus (SCN) abolished the effects of low and high doses of L-carnosine on BAT-SNA, BAT-T and BT. Furthermore, high dose treatment with L-carnosine altered c-Fos induction in the SCN and the PVN. These results suggest that l-carnosine affects BAT-SNA, BAT-T and BT in a dose-dependent manner in the rat, and that the SCN may be involved in these effects.

Role of mast cell chymase in allergen-induced biphasic skin reaction.

Intradermal injection of human chymase (EC 3.4.21.39) into the mouse ear elicited an edematous skin reaction in a biphasic manner, with a transient reaction peaking at 1 hr, followed by a delayed response persisting for at least 24hr. The kinetics of this reaction was analogous to the biphasic skin reaction induced by ascaris extract in actively sensitized mice. A similarity between the two dermatitis models was also shown by histological analysis, i.e. accumulation of inflammatory cells was observed exclusively in the later phases of the skin reaction. A chymase inhibitor, SUN-C8077 [3-(3-aminophenylsulfonyl)-7-chloroquinazorine 2,4(1H, 3H)-dione], significantly inhibited both the early- and late-phase responses of the skin reaction induced by ascaris extract. These findings suggest that chymase may play an important role in the allergen-induced biphasic skin reaction. A histamine receptor antagonist, homochlorcyclizine, inhibited the early-phase but not the late-phase of the chymase-induced skin reaction. In addition, human chymase showed chemotactic activity to human polymorphonuclear leukocytes in vitro. Mast cell chymase may participate in the two phases of allergic skin inflammation by two distinct mechanisms, i.e. histamine- and leukocyte-dependent mechanisms, respectively.

Preventive effect of L-carnosine on ischemia/reperfusion-induced acute renal failure in rats.

We investigated the effect of L-carnosine (beta-alanyl-L-histidine) on ischemic acute renal failure in rats. Ischemic acute renal failure was induced by occlusion of the left renal artery and vein for 45 min followed by reperfusion, 2 weeks after contralateral nephrectomy. Renal function in untreated acute renal failure rats markedly decreased at 1 day after reperfusion. Pre-ischemic treatment with L-carnosine dose-dependently (1, 10 microg/kg, i.v.) attenuated the ischemia/reperfusion-induced renal dysfunction. Histopathological examination of the kidney of untreated acute renal failure rats revealed severe renal damage, which was significantly suppressed by pre-treatment with L-carnosine, at each dose given. In untreated acute renal failure rats, norepinephrine concentrations in renal venous plasma remarkably increased within 2 min after reperfusion and thereafter rapidly decreased. Pre-ischemic treatment with L-carnosine at a dose of 10 microg/kg significantly depressed the elevated norepinephrine level. On the other hand, although the higher dose of L-carnosine given 5 min after reperfusion tended to ameliorate the renal dysfunction after reperfusion, the improvement was moderate compared with those seen in pre-ischemic treatment. These results indicate that L-carnosine prevents the development of ischemia/reperfusion-induced renal injury, and the effect is accompanied by suppression of the enhanced norepinephrine release in the kidney immediately after reperfusion. Thus, the preventing effect of L-carnosine on ischemic acute renal failure is probably through the suppression of enhanced renal sympathetic nerve activity induced by ischemia/reperfusion.

Possible role of L-carnosine in the regulation of blood glucose through controlling autonomic nerves.

Mammalian muscles synthesize L-carnosine, but its roles were unknown. Previously, we found in rats that the administration of a certain amount of L-carnosine elicited an inhibition of the hyperglycemia induced by the injection of 2-deoxy-D-glucose (2DG) into the lateral cerebral ventricle (LCV), and that intravenous injection of L-carnosine inhibited sympathetic nerves and facilitated the parasympathetic nerve. Moreover, the suppressive effect of L-carnosine on the hyperglycemia induced by 2DG was eliminated by thioperamide, a histaminergic H3 receptor. These findings suggested that L-carnosine might control the blood glucose level through regulating autonomic nerves via H3 receptor. To further clarify the function of L-carnosine, we examined its role in the control of the blood glucose. In this experiment, the following results were observed in rats: (i) A certain amount (0.01% or 0.001%) but not a larger amount (0.1%) of L-carnosine given as a diet suppressed the hyperglycemia induced by LCV-injection of 2DG (2DG-hyperglycemia); (ii) LCV-injection but not the injection into the intraperitoneal space (IP) of a certain amount of L-histidine suppressed the 2DG-hyperglycemia; (iii) treatments of diphenhydramine, an H1 antagonist, and alpha-fluoromethylhistidine, an inhibitor of histamine-synthesizing enzyme, reduced the 2DG-hyperglycemia; (iv) the plasma L-carnosine concentration and carnosinase activity showed daily changes; (v) the plasma L-carnosine concentration was significantly lower in the streptozotocin-diabetic rats; (vi) exercise by a running wheel tended to increase carnosine synthase activity in the gastrocnemius muscle and elevated the plasma L-carnosine concentration in the dark (active) period, and enhanced the plasma carnosinase activity in the light period; (vii) IP-injection of certain amount of L-carnosine stimulated the feeding response to IP-injection of 2DG. These findings suggest a possibility that L-carnosine released from muscles due to exercise functions to reduce the blood glucose level through the regulation of the autonomic nerves.