AIM: To contrast the effects of various modifications of body fluid volumes on thirst as reported by healthy volunteers. METHODS: Ten male volunteers aged between 19 and 37 years(mean 22 years) underwent four experime...AIM: To contrast the effects of various modifications of body fluid volumes on thirst as reported by healthy volunteers. METHODS: Ten male volunteers aged between 19 and 37 years(mean 22 years) underwent four experiments each, which comprised infusion of 400-800 m L of acetated Ringer's solution and intake of 600 m L of tap water. Half of the experiments were preceded by volume depletion(median 1.7 L) with furosemide. A visual analogue scale(0-100 mm) was used to assess perceived thirst during each experiment. RESULTS: Volume depletion(P < 0.001) and tap water(P < 0.03) both affected thirst by 13 mm per L of fluid, whereas spontaneous diuresis and infusion of Ringer's acetate did not significantly change the thirst rating(multiple regressions). More detailed analyses showed that the volume depletion increased the median(25th-75th percentiles) thirst rating from 28 mm(21-43) to 59 mm(46-72, P < 0.001) while no change occurred in those who were only slightly thirsty(< 30 mm) before the volume depletion began. Ringer's solution alleviated thirst in those who were very thirsty, but tended to increase thirst in the volunteers who were not thirsty before the infusion. Similarly, hydration with tap water decreased thirst(by 24 mm, P < 0.04) in those who were thirsty(> 60 mm) while the others reported no change.展开更多
Thirst, which provides the motivation to drink, is an important component of the coordinated sequence of physiological responses that maintain the volume and composition of body fluids. Special structures in the centr...Thirst, which provides the motivation to drink, is an important component of the coordinated sequence of physiological responses that maintain the volume and composition of body fluids. Special structures in the central nervous system like periventricular organs detect changes in these parameters continuously. The present study investigated the interaction between dopaminergic and angiotensinergic systems on water intake in adult male rats. Intracerebroventricular (ICV) injections were carried out in all experiments after 24 h deprivation of water intake. After the deprivation interval, the volume of consumed water was measured for 1h. Administration the angiotensinergic (AT1) receptor antagonist Losartan (45 μg/rat), and the dopaminergic antagonist Chlorpromazine (40 μg/rat) significantly decreased water intake when compared to saline-treated controls. In contrast, ICV microinjection of the dopaminergic agonist Bromocriptine (10 μg/rat) significantly increased water intake when compared to saline-treated controls. ICV injection of Bromocriptine 15min after Losartan administration was able to attenuate the inhibitory effect of Losartan on water intake, whereas administration of Chlorpromazine 15 min after Losartan was unable to change the Losartan effect. These results suggest that the dopaminergic system interactions with the angiotensinergic system to regulate water intake through circumventricular organs. Dopaminergic and angiotensinergic neurons can monitor and regulate water intake via the stimulatory and inhibitory effects on each other, respectively.展开更多
China accounts for more than 20 percent of the world’s global energy demand.As it is known to all that China surpassed the U.S.to become the world’s biggest energy consumer in 2009.Today the race is still neck and n...China accounts for more than 20 percent of the world’s global energy demand.As it is known to all that China surpassed the U.S.to become the world’s biggest energy consumer in 2009.Today the race is still neck and neck.CNPC in running for Iran energy projects Chinese oil giant among 29 firms to bid for tenders as a nation recovers from international sanctions展开更多
IMAGINE Beijingers drinking water brought to the capital from more than 1,000 km away. from the Danjiangkou Reservoir on a branch of the Yangtze River in Hubei Province! Incredible but now it becomes true.
文摘AIM: To contrast the effects of various modifications of body fluid volumes on thirst as reported by healthy volunteers. METHODS: Ten male volunteers aged between 19 and 37 years(mean 22 years) underwent four experiments each, which comprised infusion of 400-800 m L of acetated Ringer's solution and intake of 600 m L of tap water. Half of the experiments were preceded by volume depletion(median 1.7 L) with furosemide. A visual analogue scale(0-100 mm) was used to assess perceived thirst during each experiment. RESULTS: Volume depletion(P < 0.001) and tap water(P < 0.03) both affected thirst by 13 mm per L of fluid, whereas spontaneous diuresis and infusion of Ringer's acetate did not significantly change the thirst rating(multiple regressions). More detailed analyses showed that the volume depletion increased the median(25th-75th percentiles) thirst rating from 28 mm(21-43) to 59 mm(46-72, P < 0.001) while no change occurred in those who were only slightly thirsty(< 30 mm) before the volume depletion began. Ringer's solution alleviated thirst in those who were very thirsty, but tended to increase thirst in the volunteers who were not thirsty before the infusion. Similarly, hydration with tap water decreased thirst(by 24 mm, P < 0.04) in those who were thirsty(> 60 mm) while the others reported no change.
文摘Thirst, which provides the motivation to drink, is an important component of the coordinated sequence of physiological responses that maintain the volume and composition of body fluids. Special structures in the central nervous system like periventricular organs detect changes in these parameters continuously. The present study investigated the interaction between dopaminergic and angiotensinergic systems on water intake in adult male rats. Intracerebroventricular (ICV) injections were carried out in all experiments after 24 h deprivation of water intake. After the deprivation interval, the volume of consumed water was measured for 1h. Administration the angiotensinergic (AT1) receptor antagonist Losartan (45 μg/rat), and the dopaminergic antagonist Chlorpromazine (40 μg/rat) significantly decreased water intake when compared to saline-treated controls. In contrast, ICV microinjection of the dopaminergic agonist Bromocriptine (10 μg/rat) significantly increased water intake when compared to saline-treated controls. ICV injection of Bromocriptine 15min after Losartan administration was able to attenuate the inhibitory effect of Losartan on water intake, whereas administration of Chlorpromazine 15 min after Losartan was unable to change the Losartan effect. These results suggest that the dopaminergic system interactions with the angiotensinergic system to regulate water intake through circumventricular organs. Dopaminergic and angiotensinergic neurons can monitor and regulate water intake via the stimulatory and inhibitory effects on each other, respectively.
文摘China accounts for more than 20 percent of the world’s global energy demand.As it is known to all that China surpassed the U.S.to become the world’s biggest energy consumer in 2009.Today the race is still neck and neck.CNPC in running for Iran energy projects Chinese oil giant among 29 firms to bid for tenders as a nation recovers from international sanctions
文摘IMAGINE Beijingers drinking water brought to the capital from more than 1,000 km away. from the Danjiangkou Reservoir on a branch of the Yangtze River in Hubei Province! Incredible but now it becomes true.
