A comparison of voluntary salt-intake behavior in Nax-gene deficient and wild-type mice with reference to peripheral taste inputs

The Na(x) channel, a subfamily of voltage-gated sodium channels, is thought to be a specific sodium receptor in the central nervous system. Our previous study revealed that Na(x)-gene-deficient mice consumed excessive amounts of NaCl even under water-deprived conditions. In the present study, to investigate whether the peripheral taste inputs are involved in the abnormal intake of salt in Na(x)-deficient mice (homo), voluntary intake of various taste solutions in homo and wild-type mice (wild) was examined under non-deprived conditions. Homo showed a higher preference for 0.15 M NaCl solution than wild. Preference ratios for other basic tastants were identical between groups. Transection of the chorda tympani (CT) or the glossopharyngeal (GP) nerve had little effect on salt-intake behavior in homo and wild. Although combined transection of the superior laryngeal (SL) and GP nerves decreased NaCl intake in homo but not in wild, there were no differences in preference ratios for NaCl in homo before and after SL+GP transection. On the other hand, preference ratios for NaCl in wild tended to increase after combined SL and GP transection. Consequently, preference ratios for NaCl after SL+GP transection were no different between homo and wild. While electrophysiological responses of the CT and the GP to various taste solutions were indistinguishable between homo and wild, those of the SL to NaCl in homo were smaller than those in wild only at lower concentrations (0.01 and 0.03 M). Thus, chemosensory inputs from the oro-pharyngeal regions had little effect on abnormal salt intake in homo, if any. From these results, it is suggested that the higher preference for NaCl in homo is mainly due to the lack of Na(x) channels in the central nervous system.     

U-shaped Effect of Drinking and Linear Effect of Smoking on Risk for Stomach Cancer in Japan

A case-control study was conducted to evaluate the relationship between smoking or drinking doses and risk for stomach cancer, and to clarify whether the relationship is dose-dependent or U-shaped. Smoking dose was categorized as 0,1–399, 400–799, or 800+ cigarette-years, and drinking dose as 0, occasional/0.1–134.9, 135–1349.9, or 1350+ alcohol-years (ml of pure alcohol intake per day multiplied by years of drinking). Helicobacter pylori status was determined by serology for adjustment. Using logistic regression, the adjusted effects of smoking and drinking doses on risk for stomach cancer were calculated for both genders. Among male subjects, the odds ratios (95% confidence intervals (CIs)) were 1.29 (0.76, 2.18) for 1–399, 1.71 (1.05, 2.80) for 400–799 and 2.46 (1.49, 4.07) for 800+ cigarette-years compared with never-smokers, and 1.89 (0.97, 3.69) for never-drinkers, 2.82 (1.63, 4.86) for 135–1349.9 and 2.84 (1.97, 4.83) for 1350.0+, compared with occasional/0.1–134.9 alcohol-years. Among female subjects, they were 0.44 (0.20, 1.00) for 1–399 and 2.471 (0.91, 6.68) for 400+ cigarette-years compared with never-smokers, and 1.54 (0.90, 2.63) for never-drinkers and 1.39 (0.66, 2.93) for 135.0+ alcohol-years. Smoking seems to exert a linear effect and drinking, a J- or U-shaped effect on risk for stomach cancer, although there might be a dip of risk in light smokers among female subjects.     

瑞安市欠发达村饮用水水质分析

目的:了解瑞安市欠发达村饮用水水质卫生状况,为保证水质质量和工程有效运行提供决策依据。方法:收集2005年1月~2007年6月,260个村235份水样检测报告书;按《生活饮用水检验规范2001》、《农村实施〈生活饮用水卫生标准〉准则》进行检测评价。结果:水质总合格率为28.9%。细菌菌落总数合格率为63.4%,总大肠菌群合格率为68.1%,肉眼可见物合格率为51.1%,浑浊度合格率为88.1%。色度、pH值、铁、锰、硝酸盐等指标合格率分别为99.1%、98.3%、97.9%、99.6%、99.6%。结论:我市欠发达地区饮用水源水质量较好,但入户水质合格率低。如果去除肉眼可见物和细菌学指标影响,合格率将达86.4%以上。必须加强净化和消毒。     

垃圾场污水对下游饮用水污染的调查报告

我们对成都市垃圾场渗出的污水影响下游水质情况进行调查发现：垃圾场污水主要造成下游河水的感官指标发生恶变，而沿岸的河边井由于土层的过滤作用使井水的感官指标基本达到饮用水卫生标准，但细菌学指标仍严重超标。本文提出应积极进行农村改水工作，加强饮水消毒，同时在建垃圾场时应考虑污水排入的河流本身的自净能力     

Effects of acute or chronic administration of low doses of a dopamine agonist on drinking and locomotor activity in the rat

Low doses of piribedil (0.25–5.0 mg/kg) administered acutely produced reliable decrements in locomotor activity in thirsty and non-thirsty animals, the greatest effect occurring at the highest dose. A sequence of ten daily injections of piribedil produced indications of the development of tolerance, at the two highest doses (2.5 and 5.0 mg/kg) in thirsty animals. The smallest doses used, given either acutely or chronically, produced a weak enhancement of drinking behaviour within the first 15 min of a drinking test, as shown by a reduction in latency to drink and an increase in the amount of water consumption. Tolerance did develop with respect to drinking behaviour; animals treated chronically with piribedil displayed higher levels of drinking at several dose levels when compared with acutely treated subjects. The tolerance displayed at the two highest doses could have a close affinity with that shown with regard to locomotor activity.     

Capacitive sensor for lick-by-lick recording of drinking.

An electronic device senses the touching of water by the animal's tongue; and each lick is recorded distinctly as a deflection on paper by an ascillograph. From these traces lick rate and any variations therein may be determined.     

Physiological and behavioral effects of parachlorophenylalanine in the rat

The effect of parachlorophenylalanine (PCPA 300 mg/kg i.p.) on several physiological and behavioral parameters was investigated with telemetric methods in the unrestrained rat. Body temperature did not change with the exception of an immediate and short-lasting decrease after drug injection. Food and water intake were maximally depressed on the day following drug administration, and recovered gradually during the subsequent days, drinking more rapidly than feeding. Click-evoked potentials recorded from the auditory cortex and inferior colliculus maintained their typical waveforms during synchronized and desynchronized sleep indicating that PCPA does not produce a qualitative change of the sleep stages. A short-lasting increase of the potentials was observed after drug injection. PCPA exerted profound changes on motor activity. The activity during the light periods was significantly increased. However, motor behavior was altered more in its temporal pattern than in intensity, especially during the dark periods. The circadian rhythms of feeding, drinking and motor activity were attenuated. Since the time-course of these changes corresponds to that known for serotonin depletion in the brain, serotoninergic neuronal mechanisms may play a major role in the organization of behavioral rhythms.This study was supported by the Swiss National Science Foundation, grant no. 3.693.71, and by the Hartmann-Mueller Foundation. Parachlorophenylalanine was supplied by the courtesy of Pfizer AG, Zürich.     

Elicitation of water ingestion in the Mongolian gerbil (Meriones unguiculatus) by intracranial injections of angiotensin II and 1-norepinephrine

Intracranial injections of Angiotensin II (AII) through permanent brain chemodes aimed for the lateral hypothalamic, lateral preoptic, or septal region evoked drinking of tap water from Mongolian gerbils in normal water balance. When lettuce was the only available free water source, AII injections elicited prolonged lettuce-eating responses. l-Norepinephrine injections did not elicit eating of food pellets but, like AII, proved to be a reliable and potent dipsogenic agent. Carbachol, a cholinergic agonist, failed to elicit any ingestive behaviors over a wide dose range. The species-typical foot-thumping behavior of the gerbil was seen during some tests with all drugs utilized. It is suggested that the dipsogenic property of AII across a wide variety of species reflects the nature of a primitive, i.e., phylogenetically old, brain mechanism shared by most mammals to deal with problems of water economy, while the organization and utilization of other central neurochemicals in thirst-related substrates may vary among species.     

Lateral hypothalamic injection of bombesin decreases food intake in rats

STUCKEY, J. A. AND J. GIBBS. Lateral hypothalamic injection of bombesin decreases food intake in rats. BRAIN RES. BULL. 8(6)617–621, 1982.—The effect of lateral hypothalamic injections of bombesin on feeding behavior was examined. Rats equipped with stainless steel cannulas directed toward the lateral hypothalamus received bilateral injections of bombesin prior to access to a liquid test diet after a 3 hr food deprivation. Bombesin in doses of 5 ng, 50 ng and 100 ng produced significant reductions in the size of the first meal. Injection of 50 ng of the biologically weak analogue [D-Trp⁸] bombesin had no effect. Injection of 5 ng or 50 ng of bombesin had no effect on deprivation-induced water intake, and injection of 50 ng of bombesin had no effect on body temperature. The food and water intake data and direct quantitative behavioral measures indicated that lateral hypothalamic injections of bombesin specifically reduced food intake. The structure-activity relationship for this effect was similar to those for other actions of bombesin. A bombesin-like peptide in the lateral hypothalamus or its receptors may play a role in postprandial satiety.     

Plasma angiotensin II levels and water intake following beta-adrenergic stimulation, hypovolemia, cellular dehydration and water deprivation.

A comparison of the effects of extracellular and intracellular thirst stimuli on plasma levels of angiotensin II was made in rats. The administration of polyethylene glycol and isoproterenol elicited a strong drinking response and resulted in a significant increase in plasma angiotensin II. There was a significant correlation between the volume of water intake and plasma angiotensin II levels following the injection of polyethylene glycol but not following isoproterenol. Drinking was also elicited by the administration of hypertonic saline but there was no increase in plasma angiotensin II. The results suggest that endogenously released angiotensin II contributes to extracellular thirst but not to intracellular thirst.