Application of hydroxyapatite functional graded biomaterials in human hard tissue replacement / 中国组织工程研究

BACKGROUND:Functional graded biomaterials promote the development of human hard tissue replacement.OBJECTIVE:To review the research progress of functional graded biomaterials in human hard tissue replacement.METHODS:The first author retrieved the PubMed and CNKI databases for relevant articles published from January 2010 to April 2017 using the keywords of "functional graded biomaterial,hard tissue replacement implants,preparation methods,performance evaluation,dental implants,osseous tissue" in English and Chinese,respectively.RESULTS AND CONCLUSION:Functional graded biomaterials refer to a kind of heterogeneous composite materials with controllable and programmable gradient properties on account of continuous or quasi-continuous changes in the structure and chemical composition.Hydroxyapatite is the primary choice for the material surface.Serving as an emerging biomaterial,the functional graded biomaterial has unique structure mechanism and excellent properties.It gives full play to the performance advantages of each component and reduces internal stress interface between components.Therefore,the functional graded biomaterial will be an issue of concern in the future because of the optimization of its design,preparation and performance.

Effects of tacrolimus (FK506) on heat-shock proteins 70, Bcl-2 and Bax expression in nervous tissue of acrylamide-induced rat / 中华劳动卫生职业病杂志

<p><b>OBJECTIVE</b>To investigate the effects of tacrolimus (FK506) on behavioral function and heat-shock proteins (HSP70) expression in nervous tissues of acrylamide (ACR)-induced rats.</p><p><b>METHODS</b>Totally 40 health Wistar rats were randomly divided into control group, model group, low and high doses of FK506 groups. All four groups were treated five times per week for four weeks. Gait score was measured every week. And rats were sacrificed on day 28, the cerebrum, spinal cord and sciatic nerve were dissected, and homogenized in ice bath, then the levels of HSP70 and Bcl-2, Bax were analyzed by western bloting.</p><p><b>RESULTS</b>Compared with the ACR model group, the gait score in low and high doses of FK506 groups decreased by 30.1% and 47.7% respectively in the 4th week. In the cerebrum and sciatic nerve pellet, the level of HSP70 in the FK506 groups increased by 11.6%, 33.3% and 56.3%, 58.5% (P < 0.01), but no significant changes existed in spinal cord. The level of Bcl-2 in the sciatic nerve pellet increased by 39.1% (P < 0.01) but no significant changes existed in the cerebrum and spinal cord from low dose of FK506 group. And the level of Bax in the spinal cord pellet markedly increased by 46.8% but not in cerebrum and sciatic nerve pellet; Whereas in the tissues mentioned above, the levels of Bcl-2 were enhanced remarkably by 16.3%, 14.8% and 56.0% (P < 0.01) in the high dose of FK506 group. And the level of Bax in the cerebrum and spinal cord pellet markedly increased by 16.4% and 40.2% but not in sciatic nerve. The values of Bcl-2/Bax in low and high doses of FK506 groups clearly increased by 15.9%, 33.3%, 36.9% and 30.1%, 49.1%, 60.1% (P < 0.01).</p><p><b>CONCLUSION</b>The administration of FK506 has dramatically neuroprotective effects against the development of ACR neuropathy, which may be related to up-regulating the expression of HSP70 and Bcl-2 with down-regulating the expression of Bax.</p>

Protective effect of garlic oil given at different time against acute liver injury induced by CCl4 / 中华劳动卫生职业病杂志

<p><b>OBJECTIVE</b>To observe and compare the protective effect of garlic oil against carbon tetrachloride (CCL)-induced acute liver injury.</p><p><b>METHODS</b>The experiments include 4 preventive groups and 2 therapeutic groups. In every preventive and therapeutic group, the mice were randomized into 6 groups with 15 each, including one negative control group, one solvent control group, one CCl4 model group and 3 garlic oil groups (25, 50, and 100 mg/kg body weight). Before given a single gavage of CCl4 (80 mg/kg), the mice were pretreated with garlic oil by gavage in preventive group 1 (30 days, once daily), preventive group 2 (5 days, once daily), preventive group 3 (ahead of 2 h, once), preventive group 4 (immediately, once) or the vehicle (corn oil, 10 ml/kg) in solvent control group. In therapeutic groups, the mice were gavaged garlic oil 2 h (once, in therapeutic 1) or for 5 days (once daily, in therapeutic 2) after administration CCl. After 24 h of the last administration, blood was collected and centrifuged at 2500 r/min at 4 degrees C for 10 min, and serum was removed to measure ALT and AST activities. The liver was dissected, weighed to calculate the liver coefficient (relative liver weight). At the same time, the liver samples were studied by histological examinations.</p><p><b>RESULTS</b>Compared with negative group, the liver coefficient and the activities of ALT and AST in serum of model group were increased remarkably (P < 0.01). Compared with CCl model group, the liver coefficient and the activities of ALT and AST in serum were decreased significantly (P < 0.01) by garlic oil dose-dependently in each preventive group. Simultaneously, histological assessment showed that garlic oil effectively alleviated hepatocyte injuries induced by CCl4. Comparing the preventive effects of garlic oil in every group, it was better in preventive group 3 than others. However, all indexes and histological examinations in therapeutic group 1 did not show the difference with those of CCl4 model group. In therapeutic group 2, all indexes recovered after 5 d of CCl4 administration.</p><p><b>CONCLUSIONS</b>Garlic oil can prevent acute liver injury induced by CCl4 and the effect is better in ahead of 2 h group than others.</p>

Dynamic study of neurofilament contents in rat's spinal cord induced by 2, 5-hexanedione / 中华劳动卫生职业病杂志

<p><b>OBJECTIVE</b>To investigate the dynamic changes of neurofilament contents in rat's spinal cord induced by 2, 5-hexanedione (2, 5-HD), and explore the molecular mechanism of n-hexane neuropathy.</p><p><b>METHODS</b>Male Wistar rats were administered at a dosage of 400 mg/kg/day 2, 5-HD for 2, 4 and 8 weeks respectively. HD-induced neurological defects were detected and quantified using gait score, and the relative lev-els of NF-H, NF-M, and NF-L in spinal cords of rats were determined by Western Blotting.</p><p><b>RESULTS</b>Exposure to 2, 5-HD produced progressive gait abnormalities, which suggested that the rat model of 2, 5-HD-induced neurotoxicity was established successfully. Western-Blotting results showed that NFs content in spinal cord demonstrated a progressive decline as the intoxication continued. In the supernatant fraction, compared to the controls, NF-H con-tent decreased by 15.7%, 57.0%, and 58.0% respectively after 2, 4, and 8-week treatment with 2, 5-HD (P < 0.01); accordingly, NF-M decreased by 36.0%, 61.3%, and 65.2% respectively (P < 0.01); NF-L decreased by 20.8%, 43.9%, and 44.3% respectively (P < 0.01). In the pellet fraction, the contents of NF-H in groups of 4 and 8 weeks' exposure to HD decreased by 35.6% and 43.2%, respectively (P < 0.01), and those of NF-L decreased by 26.4% and 42.1%, respectively (P < 0.01) when compared to the control. Further-more, NF-M contents in groups of 2, 4 and 8 weeks' exposure decreased by 23.3%, 33.9%, and 63.7% respectively (P < 0.01). The NFs level in spinal cords was highly correlated with gait abnormality of treated rats as the intoxication went on. Multiple correlation coefficients of NF-H, NF-M, and NF-L content with gait score of HD-treated rat were 0.8912, 0.9282 and 0.8981 (P < 0.01) respectively.</p><p><b>CONCLUSION</b>The declines of NFs are high-ly related to neurobehavioral abnormality of 2, 5-HD-treated animals, and involved in the development of n-hexane neuropathy.</p>

Effects of garlic oil on 2, 5-HD induced lipid peroxidation damage in rat nerve tissues / 中华劳动卫生职业病杂志

<p><b>OBJECTIVE</b>To investigate the effects of garlic oil (GO) against the peroxidation damage of rat nerve tissue and the peripheral motor neuropathy induced by 2, 5-HD.</p><p><b>METHODS</b>Male Wistar rats were divided into four groups, with 10 in each group. The model group, and low and high doses of GO groups were administrated with 2, 5-HD (ip, 300 mg/kg), respectively; The control group was treated with sodium chloride, five times per week for six weeks. Pretreatment with GO gavaged (40 mg/kg or 80 mg/kg) started one week be-fore 2, 5-HD treatment, and lasted to the end of the experiment. Neurobehavioral indexes were examined at the zero, second and fourth week. At the end of the experiment, the scores of the gait, and the concentration of MDA and GSH, the level of TAOC and the ability of inhibition of.OH in cerebrum, spinal cord and sciatic nerve were examined.</p><p><b>RESULTS</b>Compared with the zero week, except of the control group rats, the hind limb landing foot splay of three groups rats decreased by 44%, 50% and 49% at the fourth week, respectively without significant difference. The threshold value of balance in model, GO low and high doses groups rats decreased by 30%, 45% and 68% at the fourth week, respectively, and lower than the control group rats (P < 0.01). GO low and high doses groups rats showed the serious abnormality at the fourth week, before one week of the model group rats. The scores of gait of model, and GO low and high doses groups rats increased significantly compared with control group rats, and the GO high dose group rats were higher than model group rats (P < 0.05). Increase of the concentration of MDA, and decrease of the level of the ability of inhibition of.OH were induced by 2, 5-HD in cerebrum, spinal cord and sciatic nerve. The concentration of MDA increased, and the level of the ability of inhibition of.OH decreased (P < 0.05 or P < 0.01), respectively. The results showed that the concentration of MDA decreased, and the level of the ability of inhibition of.OH induced by GO in cerebrum, spinal cord and sciatic nerve increased, the concentration of MDA of GO low doses group rats decreased, the level of the ability of inhibition of.OH increased, the concentration of MDA of GO high doses group rats decreased (P < 0.01) respectively, and the level of the ability of inhibition of.OH increased (P < 0.01) in nerve tissue.</p><p><b>CONCLUSION</b>GO has antagonist effect on the 2, 5-HD induced peroxidation damage, but can not improve the function of the peripheral motor nerve, indicating that the lipid peroxidation does not play an important role in 2, 5-HD neurotoxicity.</p>

Expression changes of cyclin dependent kinase 5/p35 in nerve tissues of 2, 5-hexanedione intoxicated rats / 中华劳动卫生职业病杂志

<p><b>OBJECTIVE</b>To explore the role of cyclin dependent kinase 5 (CDK5) in 2, 5-hexanedione (HD)-induced neuropathy.</p><p><b>METHODS</b>Thirty male Wistar rats weighted 200 approximately 240 g were divided randomly into three groups, i.e. control group, 200 mg/kg HD group and 400 mg/kg HD group (n = 10 for each group). HD was administered to rats by intraperitoneal injection at dosage of 200 or 400 mg/kg for 8 weeks (five times per week) to establish the intoxicated rats model. The relative contents of CDK5, p35 and p25 were determined in cerebrum, spinal cord and sciatic nerve of rats by Western Blotting.</p><p><b>RESULTS</b>Compared with that of the control group rats, p35 contents were significantly decreased (P < 0.01) in the cytosolic fractions of cerebrum and spinal cord in both the 200 and 400 mg/kg HD intoxicated rats, while in the membrane fractions of spinal cord and sciatic nerve, p35 contents were increased significantly (P < 0.01). The changes of p25 showed the same pattern with p35. P25 contents were significantly reduced (P < 0.05) in the cytosolic (cerebrum and spinal cord) and membrane (cerebrum) fractions of both HD-treated rats and were elevated (P < 0.01) in the membrane fraction of spinal cord and cytosolic fraction of sciatic nerve. The relative amounts of CDK5 were significantly decreased (P < 0.01) in the cytosolic and membrane fractions of cerebrum in both the 200 and 400 mg/kg HD intoxicated rats. Except for membrane fraction of sciatic nerve, the significant increased (P < 0.01) of CDK5 were observed in the spinal cord and sciatic nerve of both the 200 and 400 mg/kg HD treated rats.</p><p><b>CONCLUSION</b>HD can induce significant changes of CDK5 and its activators p35, p25 in nerve tissues, which may be related to the neuropathy induced by HD.</p>

In vivo and in vitro determination of changes of electrophysiology in rats with allyl chloride poisoning / 中华劳动卫生职业病杂志

<p><b>OBJECTIVE</b>To compare the results of in vivo and in vitro in determination of the changes of allyl chloride (AC)-induced electrophysiology in rats sciatic nerve.</p><p><b>METHODS</b>Ninety male Wistar rats weighted 180 approximately 220 g were divided randomly into two groups, i.e. experimental group (n=40) and control group (n=50). The rats in experimental group were treated with AC dissolved in corn oil (200 mg/kg ip 3 days/week) by gavage for 12 weeks. Electrophysiological indexes of each group were determined on 3, 6, 9 and 12 weeks of AC intoxication. The indexes included measurements of sciatic nerve conduct velocity (NCV), compound action potential amplitude (CAPA), potential latency (PL), time course (TC), threshold potential (TP) and max stimulate potential (MSP).</p><p><b>RESULTS</b>Compared to the corresponding time-matched control rats, on 6, 9 and 12 weeks of AC intoxication, NCV were decreased by 23.6%, 40.4% and 48.6% (P<0.05, P<0.01) in vivo, while in vitro it was decreased by 15.4% (P<0.05) on 12 week, CAPA were reduced by 31.7% in vivo, while in vitro it was reduced by 31.7%, 38.9% and 58.9% (P<0.05, P<0.01), respectively, PL were prolonged 22.6% and 40.7% (P<0.01) on 9, 12 weeks in vivo, while in vitro it was prolonged 8.0% (P<0.05), TC were increased 22.5%, 34.6% and 47.5% (P<0.01) in vivo, while in vitro it was increased 11.6%, 20.0% (P>0.05) and 19.5% (P<0.01), respectively, TP were elevated 12.1% (P>0.05), 32.3% and 40.0% (P<0.05) in vivo, while in vitro it was elevated 16.4% (P>0.05), 29.2% and 35.6% (P<0.05), respectively, MSP were increased 40.5% (P>0.05), 69.0% and 86.5% (P<0.01) in vivo, while in vitro it was increased 29.7% (P>0.05), 52.0% and 61.9% (P<0.01), respectively.</p><p><b>CONCLUSION</b>The two methods of in vivo and in vitro showed that AC could significantly affect the electrophysiology of sciatic nerve, and the time-dependent changes occurred. The NCV is the most sensitive indicator in vivo to the early diagnosis of AC intoxication, while CAPA is the most sensitive indicator in vitro.</p>

Time dependent changes in antioxidation of rat serums and sciatic nerves caused by toxicology / 中华劳动卫生职业病杂志

<p><b>OBJECTIVE</b>To study the time dependent antioxidation changes of serum and sciatic nerve in rats intoxicated with acrylamide.</p><p><b>METHODS</b>Male Wistar rats weighing 180 to 220 g were given acrylamide dissolved in physiological saline (40 mg/kg ip 3 days/week). The control groups received normal saline. The gait was observed and antioxidant indexes of rat serum and sciatic nerve were determined on 0, second, fourth, sixth, 10th week.</p><p><b>RESULTS</b>With the extension of the intoxication period, compared with the control, the contents of glutathione in serum and sciatic nerve gradually decreased (P < 0.05; after 6 and 10 weeks to 92% and 77%; after 2, 4, 6 and 10 weeks to 92%, 82%, 67% and 66%); the levels of malondialdehyde gradually increased (P < 0.05; after 4, 6 and 10 weeks to 113%, 118% and 120%; after 4, 6 and 10 weeks to 153%, 167%, 174%); the abilities of the resistance to reactive oxygen species gradually decreased (P < 0.05; after 10 weeks to 82%; after 6 and 10 weeks to 76% and 71%); the activities of glutathione peroxidase gradually increased (P < 0.05; after 2, 4, 6 and 10 weeks to 122%, 130%, 160% and 124%; after 4, 6 and 10 weeks to 134%, 152% 164%); the activities of glutathione reductase increased at early stage (P < 0.01; after 4 and 6 weeks to 300% and 217%; after 4 weeks to 142%) and decreased later (P < 0.01; 6 and 10 weeks to 59% and 33% in sciatic nerve); the activities of superoxide dismutase increased primitively (P < 0.05; after 2 weeks to 110%; after 4 weeks to 124%) and decreased later (P < 0.05; after 10 weeks to 85% in serum). The changes of antioxidant indexes in serum and sciatic nerve according to gait score were similar. The level of MDA in serum was in high correlation (P < 0.01) with that in sciatic nerve. The regression coefficients were 0.99 and 0.96 according to the administration time and gait score respectively.</p><p><b>CONCLUSION</b>The changes of the antioxidant indexes in serum and sciatic nerve of rat treated with acrylamide are time dependent. The changes in serum and sciatic nerve are similar but those in sciatic nerve are more remarkable.</p>

Adenosine reduces intracellular free calcium concentration in guinea pig ventricular myocytes / 中国应用生理学杂志

<p><b>AIM</b>To observe the effects of adenosine on intracellular calcium concentration ([Ca2+]i) level in guinea pig ventricular myocytes and to define the possible mechanisms involved.</p><p><b>METHODS</b>The effects of adenosine on [Ca2+]i were investigated in guinea pig ventricular myocytes. [Ca2+]i was detected by laser confocal microscopy and represented by relative fluorescent intensity ((FI-FI0)/FI0, %, FIo: control, FI: administration of drugs).</p><p><b>RESULTS</b>(1) Adenosine (10, 50, 100 micromol/L) reduced [Ca2+]i of ventricular myocytes in both normal Tyrode's solution and Ca(2+) -free Tyrode's solution in a concentration-dependent manner. (2) Tyrode's solution containing 30 mmol/L KCl (high K+ Tyrode's solution) induced [Ca2+]i elevation in ventricular myocytes, while adenosine (10, 50, 100 micromol/L) markedly inhibited the increase in [Ca2+]i induced by KCl. (3) Pretreatment with DPCPX (1 micromol/L) significantly reduced the effects of adenosine (100 micromol/L) in high K+ Tyrode's solution. The effects of adenosine (100 micromol/L) on [Ca2+]i in high K+ Tyrode's solution were also partially attenuated by pretreatment with L-NAME (1 mmol/L). (4) Adenosine (100 micromol/L) markedly inhibited the low concentration of ryanodine-induced [Ca2+]i increase in Ca(2+) -free Tyrode's solution. (5) When the propagating waves of elevated [Ca2+]i (Ca2+ waves) were produced by increasing extracellular Ca2+ concentration from 1 mmol/L to 10 mmol/L, adenosine (100 micromol/L) could block the propagating waves of elevated [Ca2+]i, reduce the frequency and duration of propagating waves, and reduce [Ca2+]i as well.</p><p><b>CONCLUSION</b>Adenosine may reduce the [Ca2+]i in isolated guinea pig ventricular myocytes via inhibiting Ca2+ influx and alleviating Ca2+ release from sarcoplasmic reticulum(SR). The reduction of Ca2+ influx might be due to the inhibition of voltage-dependent Ca2+ channel via adenosine A1 receptor, and NO might be involved in this process.</p>

Resveratrol inhibits neuronal discharges in rat hippocampal CA1 area / 生理学报

The effects of resveratrol on the discharges of neurons in CA1 area of rat hippocampal slices were examined by using extracellular recording technique. The results are as follows: (1) In response to the application of resveratrol (0.05, 0.5, 5.0 micromol/L, n=52) into the superfusate for 2 min, the spontaneous discharge rate of 46/52 (88.5%) neurons was significantly decreased in a dose-dependent manner; (2) Application of L-glutamate (0.2 mmol/L) into the superfusate led to a marked increase in discharge rate of all 8 (100%) slices in an epileptiform pattern. The increased discharges were suppressed by application of resveratrol (5.0 micromol/L); (3) In 7 slices, perfusion of the selective L-type calcium channel agonist, Bay K8644 (0.1 micromol/L), induced a significant increase in the discharge rate of 6/7 (85.7%) slices. The increased discharges were suppressed by application of resveratrol (5.0 micromol/L); (4) In 9 slices, perfusion of nitric oxide synthase (NOS) inhibitor N(G)-nitro-L-arginine methyl ester (L-NAME, 50 micromol/L) into the superfusate significantly augmented the discharge rate of 7/9 (77.8%) slices. Resveratrol (5.0 micromol/L) applied into the superfusate reduced the increased discharges of all 7/7 (100%) neurons; (5) In 10 units, the large-conductance Ca(2+)-activated K(+) channel blocker (tetraethylammonium chloride, TEA, 1 mmol/L) significantly increased the discharge rate of 9/10 (90%) slices. Resveratrol (5.0 micromol/L) applied into the superfusate inhibited the discharges of 8/9 (88.9%) slices. These results suggest that resveratrol inhibits the electrical activity of CA1 neurons. This effect may be related to the blockade of L-type calcium channel and a subsequent reduction of calcium influx, and probably has no association with large-conductance Ca(2+)-activated K(+) channel.

Effects of resveratrol on delayed afterdepolarization and triggered activity induced by ouabain in guinea pig papillary muscles / 生理学报

The purpose of this study was to investigate the effects of resveratrol on delayed afterdepolarization (DAD) and triggered activity (TA) induced by ouabain in guinea pig papillary muscles and the underlying mechanism. Action potentials were recorded using intracellular microelectrode technique. The results obtained are as follows: (1) DAD and TA induced by ouabain (1 micromol/L) were inhibited by pretreatment with resveratrol (30, 60, and 120 micromol/L) in a concentration-dependent manner; (2) Pretreatment with N(G)-nitro-L-arginine methyl ester (L-NAME, 1 mmol/L), a nitric oxide (NO) synthase inhibitor, failed to abolish the above effect of resveratrol (60 micromol/L ); (3) 5 micromol/L 17beta-estradiol (E(2)) or 30 micromol/L resveratrol had no effects on DAD and TA, however, resveratrol combined with E(2) at the same doses exerted significant inhibitory effects on DAD and TA; (4) Pretreatment with tamoxifen (TAM, 10 micromol/L), an inhibitor of estrogen receptor, also did not blocked the effects of resveratrol (60 micromol/L) on DAD and TA induced by ouabain. All these results indicated that resveratrol exerted an inhibitory effects on DAD and TA induced by ouabain, possibly by reducing calcium influx, which might not be mediated by NO and estrogen receptor. The antiarrhythmic effects of resveratrol may contribute to its cardioprotective action.

Resveratrol inhibits the electrical activity of subfornical organ neurons in rat / 生理学报

The effects of resveratrol on the discharges of neurons in rat subfornical organ (SFO) slices were examined by using extracellular recording technique. The results are as follows: (1) In response to the application of resveratrol (1, 5, 10 mumol/L, n=65) into the superfusate for 2 min, the spontaneous discharge rate of 60/65 (92.3%) neurons was significantly decreased in a dose-dependent manner;(2) Application of L-glutamate (0.3 mmol/L) into the superfusate led to a marked increase in discharge rate of all 12 (100%) neurons in an epileptiform pattern. The increased discharges of 10/12 (83.3%) neurons were suppressed by application of resveratrol (5 mumol/L);(3) In 8 neurons, the selective L-type calcium channel agonist, Bay K8644 (0.1 mumol/L), induced a significant increase in discharge rate of all 8 (100%) neurons. The increased discharges of all 8 (100%) neurons were suppressed by resveratrol (5 mumol/L);(4) In 14 neurons, nitric oxide synthase (NOS) inhibitor N(G)-nitro-L-arginine methyl ester (L-NAME) 50 mumol/L significantly increased the discharge rate of 11/14 (78.6%) neurons. Resveratrol (5 ?mol/L) applied into the superfusate reduced the increased discharges of 9/11 (81.8%) neurons;(5) In 12 neurons, the large-conductance Ca(2+)-activated K(+) channel blocker tetraethylammonium chloride (TEA) 1 mmol/L significantly increased the discharge rate of 10/12 (83.3%) neurons. Resveratrol (5 mumol/L) inhibited the increased discharges of 9/10 (90%) neurons. These results suggest that resveratrol inhibits the electrical activity of SFO neurons. This effect may be related to its properties of blockade of L-type voltage-gated calcium channel and nitric oxide (NO) promoting, and probably has no association with large-conductance Ca(2+)-activated K(+) channel.

Resveratrol reduces intracellular free calcium concentration in rat ventricular myocytes / 生理学报

Resveratrol (trans-3, 4', 5-trihydroxy stilbene), a phytoalexin found in grape skins and red wine, has been reported to have a wide range of biological and pharmacological properties. It has been speculated that resveratrol may have cardioprotective activity. The objective of our study was to investigate the effects of resveratrol on intracellular calcium concentration ([Ca(2+)](i)) in rat ventricular myocytes. [Ca(2+)](i) was detected by laser scanning confocal microscopy. The results showed that resveratrol (15~60 mumol/L) reduced [Ca(2+)](i) in normal and Ca(2+)-free Tyrode's solution in a concentration-dependent manner. The effects of resveratrol on [Ca(2+)](i) in normal Tyrode's solution was partially inhibited by pretreatment with sodium orthovanadate (Na3VO4, 1.0 mmol/L, P<0.01), an inhibitor of protein tyrosine phosphatase, or L-type Ca(2+) channel agonist Bay K8644 (10 mumol/L, P<0.05), but could not be antagonized by NO synthase inhibitor L-NAME (1.0 mmol/L). Resveratrol also markedly inhibited the ryanodine-induced [Ca(2+)](i) increase in Ca(2+)-free Tyrode's solution (P<0.01). When Ca(2+) waves were produced by increasing extracellular Ca(2+) concentration from 1 to 10 mmol/L, resveratrol (60 mumol/L) could reduce the velocity and duration of propagating waves, and block the propagating waves of elevated [Ca(2+)](i). These results suggest that resveratrol may reduce the [Ca(2+)](i) in isolated rat ventricular myocytes. The inhibition of voltage-dependent Ca(2+) channel and tyrosine kinase, and alleviation of Ca(2+) release from sarcoplasmic reticulum (SR) are possibly involved in the effects of resveratrol on rat ventricular myocytes. These findings could help explain the protective activity of resveratrol against cardiovascular disease.

Injection of adenosine into the renal artery activates spontaneous activity of renal afferent nerve fibers / 生理学报

The effects of injection of adenosine into the renal artery on multi- and single-unit spontaneous discharges of renal afferent nerve fibers were investigated in anesthetized rabbits. The results obtained are as follows: (1) injection of 50, 100, and 200 nmol/kg adenosine into the renal artery increased the renal afferent nerve activity (ARNA) in a dose-dependent manner with unchanged arterial pressure; (2) pretreatment with 8-cyclopenthl-1,3-dipropylxanthine (DPCPX, 160 nmol/kg), an adenosine A1 receptor antagonist, partly abolished the effect of adenosine; and (3) pretreatment with a nitric oxide synthase inhibitor N(omega)-nitro-L-arginine methylester (L-NAME, 0.1 mmol/kg) significantly enhanced the ARNA response to adenosine. The results suggest that injection of adenosine into the renal artery activates ARNA via adenosine receptors in anesthetized rabbits and that nitric oxide may be involved in regulating the activity of renal sensory nerve fibers as an inhibitory neurotransmitter.

Electrophysiological effects of nitric oxide on spontaneous activity of rabbit atrioventricular node cells / 生理学报

The electrophysiological effects of nitric oxide (NO) on spontaneous activity of rabbit atrioventricular (AV) node cells were examined using intracellular microelectrode technique. The results obtained are as follows. (1) NO donors sodium nitroprusside (SNP, 1~1000 micromol/L) and 3-morpholinosydnonimine (SIN-1, 100, 1000 micromol/L) decreased the amplitude of action potential (APA), rate of spontaneous firing (RSF), velocity of diastolic (phase 4) depolarization (VDD), and maximal rate of depolarization (V(max)) in a concentration-dependent manner. (2) Pretreatment with L-type calcium channel agonist Bay K8644 (0.25 micromol/L) completely reversed the effects of SNP (100 micromol/L) on AV node cells. (3) Elevation of Ca(2+) concentration (5 mmol/L) in superfusate antagonized the effects of SNP on AV node cells. (4) Perfusion with Ca(2+)-free K-H solution, completely abolished the effects of SNP on AV node cells. (5) Application of methylene blue (50 micromol/L), a guanylyl cyclase inhibitor, failed to abolish the inhibitory effects of SNP (100 micromol/L). All these results suggest that NO exerts a negative effect on spontaneous activity of AV node cells in rabbits. These effects are likely due to reduction in calcium influx via a cGMP-independent mechanism.

Electrophysiological effects of resveratrol on guinea pig papillary muscles / 生理学报

The purpose of this study was to investigate the electrophysiological effects of resveratrol on guinea pig papillary muscles and the underlying mechanism. Action potentials were recorded by using intracellular microelectrode technique. The results obtained are as follows: (1) In normal papillary muscles, resveratrol (30, 60, and 120 micromol/L) shortened the duration of action potential (APD) in a concentration-dependent manner. (2) In partially depolarized papillary muscles, resveratrol (60 micromol/L ) not only shortened APD, but also decreased the amplitude of action potential (APA), overshoot (OS) and maximal rate of depolarization in phase 0 (Vmax). (3) Perfusion with Ca2+-free K-H solution, completely abolished the effects of resveratrol (60 micromol/L) on papillary muscles. (4) Application of potassium channel blocker tetraethylammonium chloride (TEA, 20 mmol/L) did not prevent the effect of resveratrol (60 micromol/L) on action potential. (5) Pretreatment with NG-nitro-L-arginine methyl ester (L-NAME, 1 mmol/L), a nitric oxide (NO) synthase inhibitor, failed to abolish the effect of resveratrol (60 micromol/L). All these results indicate that the electrophysiological effects of resveratrol on guinea pig papillary muscles are likely due to the reduction of calcium influx, which might not be mediated by NO.

A simple and new type of drop recorder mainly applied in the experiment of frog heart / 中国应用生理学杂志

<p><b>AIM</b>To introduce the manufacture and use of a simple, new type of drop recorder of frog heart.</p><p><b>METHODS</b>To improve the perfusion device of (see text for symbol) and Straub method. Two electrodes of drop recorder were fixed in an injector of 20 ml. The input tube, output tube and resistance tube were all made of plastic material.</p><p><b>RESULTS</b>This device could be used to observe effects of preload, after-load, hormone and electrolyte on the cardiac output in isolated frog heart.</p><p><b>CONCLUSION</b>The new type of drop recorder was economical and could be easily operated, it could be also connected to computer. Using the new type of drop recorder, effects of various physical and chemical factors on cardiac function could be observed directly, accurately.</p>

Effect of NO on automaticity of rabbit sino-atrial node / 中国应用生理学杂志

<p><b>AIM</b>To investigate the effects of exogenous NO donors sodium nitroprusside (SNP) and 3-morpholinosydnonimine (SIN-1) on automaticity of the rabbit sino-atrial node in vitro and the action mechanism.</p><p><b>METHODS</b>The intracellular microelectrode technique is used to record the action potentials of rabbit sino-atrial node and APA (amplitude of AP), V(max) (maximal rate of depolarization), VDD (velocity of diastolic depolarization), RPF (rate of pacemaker firing) are analyzed.</p><p><b>RESULTS</b>SNP(10(-5) - 10(-2) mol/L) increased its RPF and VDD dose-dependently. 10(-3) mol/L SNP increased RPF (beats/min) from 163 +/- 10.8 to 195.0 +/- 13.1 increased VDD (mV/s) from 50.3 +/- 9.6 to 70.2 +/- 12.1 (P < 0.01). SIN-1(10(-3) - 10(-2) mol/L) also increased RPF and VDD (P < 0.01).10(-4) mo/L Methylene blue (MB), a blocker of GMP cyclase, prevented the positive chronotropic effect and increasement of VDD induced by 10(-3) mol/L SNP totally (P < 0.01). 2. CsCl (2 mmol/L), a blocker of I(f) prevented the increasement of RPF and VDD in part (P < 0.05). 3. NIF (0.46 micromol/L), a blocker of I(Ca-L, had no significant effects on chronotropic effect and increasement of VDD (P < 0.01).</p><p><b>CONCLUSION</b>Exogenous NO can increase the automaticity of rabbit sino-atrial node in vitro. The chronotropic effect is involved in NO-cGMP pathway and results from increasement of I(f) in the sino-atrial node at least in part; I(ca-L) is unlikely to play a major role in this effect.</p>