Effect of bile acids on surface tension of bronchoalveolar lavage fluid in rabbits / 南方医科大学学报

<p><b>OBJECTIVE</b>To observe changes in surface tension of bronchoalveolar lavage fluids (BALF) in rabbits with hyperbilirubinemia and the influence of bile diluents and 5 different bile acids on BALF surface tension to provide better insight into the regulatory role of bile acids on respiratory function.</p><p><b>METHODS</b>Bronchoalveolar lavage with 0.9% normal saline was carried out in 30 male New Zealand rabbits and the surface tensions of BALF were measured. The changes in BALF surface tension was measured in rabbits with hyperbilirubinemia. Different concentrations of bile diluents, normal saline, or water solutions of 5 bile acids were added into the collected BALF to test their influence on the surface tension of BALF.</p><p><b>RESULTS</b>The BALF from rabbits with hyperbilirubinemia showed a significantly increased surface tension (P<0.05). The bile diluents (1:15, 1:10, and 1:5) added into the BALF increased the surface tension of the BALF by 21.15%, 26.09%, and 19.64%, respectively. Among the water solutions of the 5 bile acids, UDCA produced no significant influence on the surface tension of BALF while CDCA, CA, LCA, and DCA increased the surface tension by 16.10%, 21.66%, 14.21%, and 13.05%, respectively.</p><p><b>CONCLUSION</b>The surface tension of BALF increases significantly during hyperbilirubinemia. Bile diluents as well as the free bile acids CDCA, CA, LCA and DCA, but not UDCA, can increase the surface tension of BALF, suggesting that these bile acids may emulsify pulmonary alveolar surfactants to increase the alveolar surface tension.</p>

Effect of high blood levels of bile acid on respiratory functions of New Zealand rabbits / 南方医科大学学报

<p><b>OBJECTIVE</b>To compare the patterns of respiratory function variations resulting from the classical reflex of blood pressure fall and high blood levels of bile acid, so as to provide evidence for the regulation of respiratory function via bile acids.</p><p><b>METHODS</b>Seventy New Zealand male Rabbits, under general anesthesia with 20% urethane, were subjected to tracheal intubations and carotid artery cannulations via median incisions of the neck. Using a biological signal acquisition system, the changes in the breathing and blood pressure were observed in response to stimulation of the pneumogastric nerves or to ear vein injections of diluted bile acids or the water solutions of 5 dissociated bile acids.</p><p><b>RESULTS</b>Stimulation of the pneumogastric nerves and injections of diluted bile acids both lowered the blood pressure without significant differences in the total reaction time (T). However, the total respiratory reaction time of bile acids, RT(bile acids), was 9-10 times longer than the total reaction time of blood pressure T(bile acids) (P<0.001). The peak-peak values of respiratory range RR(bile acids) were higher than that RR(pneumogastric nerves)resulting from the classical reflex (P<0.001). In the interval of RT1(bile acids), the values of RR(bile acids) were significantly higher than those of RR(bile acids) in RT2(bile acids) interval. UDCA produced no significant influence on blood pressure or respiratory function (P<0.05) as the other 4 dissociated bile acid reagents did (P<0.001).</p><p><b>CONCLUSION</b>High blood levels of bile acids not only act through reflex factors but also have direct effects on respiratory function regulation. Under our experimental conditions, UDCA has no effect on blood pressure or respiratory function, but the other 4 dissociated bile acid reagents can all dose-dependently lower blood pressure and significantly affect respiratory function.</p>

Aβ5～35 and Apo E4 enhance neuronal intracellular free Ca2+ / 中国药理学通报

AIM　To study the effects of Aβ25～35 and Apo E4 on neuronal intracellular free Ca2+(［Ca2+］i). METHODS　Hippocampal and cortical neurons suspension of newborn(0～3 days) SD rats was produced. After incubated with fura-2/AM,the neurons suspension was divided into four groups: control, Aβ25～35, Apo E4, Aβ25～35+Apo E4. Each groups ［Ca2+］i was measured using a RF-5000 dual wavelength spectrofluorometer after incubated with double distilled water, Aβ25～35, Apo E4, Aβ25～35+Apo E4 for 3 min, respectively. The neurons outocorrelation function(ACF) of the scattering light intersity was analyzed by the microscope quasi-elastic light scattering(MQLS) technique The frequency shift line width by ACF. The Γ can sympolize the cell menbrane flilidity. RESULTS　Both Aβ25～35 and Apo E4 could significantly enhance hippocampal and cortical neurons rest ［Ca2+］i, furthermore, the effect of 5 μmol*L-1 Aβ25～35 was higher than the effect of 1 μmol*L-1 Aβ25～35 (P<0.05), and they also amplified KCl-induced rise in ［Ca2+］i in hippocampal and cortical neurons(P<0.05). The interaction of Aβ25～35 and Apo E4 could also significantly enhance hippocampal and cortical neurons rest ［Ca2+］i andamplified KCl-induced rise in ［Ca2+］i in hippocampal and cortical neurons(P<0.05), but they had no synergic or additive effect.The frequency shift line widith Γ of both hippocampal and cortical neurons were decreased by both Aβ25-35 and ApoE4. CONCLUSION　Aβ25～35 and Apo E4 could enhance neuronal intracellular free Ca2+, amd decrease meirpma; ,e,brame f;iodotu. But their interaction had no synergic or additive effect. It suggested that the amplified effect of Aβ25～35 and Apo E4 on neuronal ［Ca2+］i and membane fluidity may be relative to their neurotoxity.

A?_(5～35) and Apo E4 enhance neuronal intracellular free Ca~(2+) / 中国药理学通报

AIM To study the effects of A? 25～35 and Apo E4 on neuronal intracellular free Ca 2+ ([Ca 2+ ] i). METHODS Hippocampal and cortical neurons suspension of newborn(0～3 days) SD rats was produced. After incubated with fura 2/AM,the neurons suspension was divided into four groups: control, A? 25～35 , Apo E4, A? 25～35 +Apo E4. Each groups [Ca 2+ ] i was measured using a RF 5000 dual wavelength spectrofluorometer after incubated with double distilled water, A? 25～35 , Apo E4, A? 25～35 +Apo E4 for 3 min, respectively. The neurons outocorrelation function(ACF) of the scattering light intersity was analyzed by the microscope quasi elastic light scattering(MQLS) technique The frequency shift line width by ACF. The ? can sympolize the cell menbrane flilidity. RESULTS Both A? 25～35 and Apo E4 could significantly enhance hippocampal and cortical neurons rest [Ca 2+ ] i, furthermore, the effect of 5 ?mol?L -1 A? 25～35 was higher than the effect of 1 ?mol?L -1 A? 25～35 ( P