Zhongguo yao li xue bao = Acta pharmacologica Sinica最新文献

Aim: To explore the role of cytosolic free calcium ([Ca2+]i) in apoptosis induced by coxsackievirus B3 (CVB3) in cultured cardiomyocytes of rats.

Methods: Primary cultured cardiomyocyte was prepared from Wistar rats ages 2-3 d. The apoptosis in cardiomyocyte was determined by terminated deoxynucleotide transferase directed d-UTP nick and end labeling (TUNEL) method, and the apoptosis was observed under a transmission electron microscope. [Ca2+]i in single cardiomyocyte loaded with Fluo 3-AM was measured by confocal microsorope.

Results: (1) The concentration of CVB3 in the medium reached the peak at 24 h after CVB3 infection. (2) The apoptotic cells were not found in CVB3-infected cardiomyocyte in first 10 h, but amounted to 5% at 17 h, 60% at 24 h, and 90% at 36 h. (3) The peak value of [Ca2+]i elevation reached at 17 h after CVB3 infection (P < 0.01). (4) The characteristics of apoptosis was also seen by transmission electron microscope.

Conclusion: CVB3 induced the apoptosis in cultured cardiomyocyte, and [Ca2+]i mobilization was involved in the signal transduction process in apoptosis cells, and played an important role especially in the early stage of apoptosis induced by CVB3.

Aim: To study the effect of four kinds of antifertility agents anordrin(Ano), droloxifene(Dro), nomegestrol (Nom), and mifepristone (Mif) on luteal cell apoptosis.

Methods: Cultured rat luteal cells were incubated with different agents. HE stain was used to observe morphological changes. Extracted DNA was electrophoresed on agarose gel. Apoptotic cells were quantitated by flow cytometry.

Results: All 4 drugs reduced cell viability. Dro induced apoptosis while the other 3 drugs induced necrosis. Typical DNA ladders were observed after cells were incubated with Dro and there were 15.4%, 75.4%, or 90.5% apoptotic cells after treatment with Dro 1.25, 2.5, or 3.75 mg.L-1, respectively.

Conclusion: Dro induced apoptosis while Ano, Nom, and Mif induced necrosis in cultured rat luteal cells.

Aim: To study the systemic anti-inflammatory actions of interleukin-1 (IL-1) blockers, OB-101 and OB-186.

Methods: Prevention of palm swelling induced by carrageenin injection was used as an animal model of systemic anti-inflammation efficacy.

Results: Both OB-101 and OB-186 (10-30 mg.kg-1) were approximately 10-30-fold more potent than aspirin (300 mg.kg-1) to inhibit carrageenin-induced systemic inflammation. The LD50 of OB-101 and OB-186 were at least 20 g.kg-1 i.g., indicating that they were extremely safe agents with a therapeutic index (LD50/ED50) of at least 2000.

Conclusion: These IL-1 blockers are extremely safe systemically and are useable for the treatment of systemic inflammation such as rheumatoid arthritis.

Aim: To study the mechanism underlying the difference in physical dependence potential of morphine (Mor), methadone (Met), buprenorphine (Bup), etorphine (Eto), and dihydroetorphine (DHE).

Methods: Adenylate cyclase of NG108-15 cells were used for studying the effects of different opiates on cAMP second messenger system.

Results: Bup, DHE, and Eto were distinct from Mor in naloxone-precipitated rebound response of cAMP in NG108-15 cells chronically treated with these opiates. Naloxone given to NG108-15 cells treated with Mor for 24 h produced marked rebound response of adenylate cyclase. While no such rebound response was detected when the cells were treated with Bup, DHE, and Eto for 24 h. The naloxone-induced rebound response of cAMP in chronic Met-treated NG108-15 cells was also lower than that in chronic Mor-treated NG108-15 cells. Following a prolonged exposure to Bup, DHE, and Eto for 72 h, the naloxone-induced rebound response of cAMP in these cells was still markedly lower than that in Mor-treated cells. The substitution of Mor with Bup, Met, DHE, and Eto inhibited naloxone-induced rebound response of cAMP in chronic Mor-treated NG108-15 cells.

Conclusion: There were distinct differences among these opiates in regulating cAMP second messenger system, which was related to their physical dependence potential.

Aim: To observe the selective effects of alfuzosin (Alf) and doxazosin (Dox) on the urethral pressure by different administration routes.

Methods: The urethral pressure of the anesthetized cat was increased by electric stimulation of the hypogastric nerve. The different effects of Alf or Dox on the arterial blood pressure and urethral pressure between intraduodenal administration (i.d.) and intravenous infusion (i.v.) were compared.

Results: When the hypogastric nerve was stimulated by electric stimulation (10 Hz, 25 V), the ratios of ED20(BP)/ED50(UP) i.d. to ED20(BP)/ED50(UP) i.v. were 10.9:4.3 for Alf, and 3.1:2.1 for Dox. The reduction in urethral pressure induced by i.d. Alf was greater than that by i.v. Alf. Dox did not show any difference in its effects by 2 administration routes.

Conclusion: Intraduodenal administration of Alf, but not Dox, selectively decreased the urethral pressure elevated by electric stimulation. The uroselectivity of i.d. Alf was not due to the species difference in its bioavailability and biotransformation.

Aim: To study the antagonism of sincalide to the effect of morphine and its mechanism.

Methods: The electrophysiologic and mechanic activities of rat jejunum in vitro were recorded.

Results: Acetylcholine (ACh, 150 nmol.L-1) increased the spike potential amplitude (SPA) and the number (SPN) of rat jejunum in vitro, followed by an increase of jejunal contraction amplitudes (CA), showing a positive correlation. Morphine 330 nmol.L-1 inhibited the potentiation of ACh, showing a negative correlation. Sincalide 0.7 nmol.L-1 antagonized the effects of morphine, i.e., the SPA and SPN were increased again, followed by an increase of CA. CCK-A receptor antagonist devazepide (10 nmol.L-1) reversed the antagonism of sincalide to the effect of morphine.

Conclusion: Sincalide antagonized the effect of morphine which inhibited the potentiation of ACh on jejunal activities in vitro. The antagonistic effect of sincalide on morphine was mainly mediated by CCK-A receptor.

Aim: To study the influences of calcium channel blockers on calcium release-activated calcium currents (ICRAC) in rat hepatocytes.

Methods: Whole-cell patch-clamp technique was used.

Results: The peak amplitude of ICRAC was -0.41 nA +/- 0.09 nA (n = 15), its reversal potential was about 0 mV. Verapamil (Ver), diltiazem (Dil), and nifedipine (Nif) decreased ICRAC strikingly, without affecting its reversal potential. The inhibitory rate of Ver 5 mumol.L-1 was 40% +/- 12% (n = 3), Ver 50 mumol.L-1 reduced the peak amplitude of ICRAC from -0.49 nA +/- 0.12 nA to -0.20 nA +/- 0.09 nA (P < 0.01 vs control, n = 5). The inhibitory rate was 57% +/- 15%. Dil 50 mumol.L-1 and Nif reduced ICRAC from -0.43 nA +/- 0.10 nA to -0.29 nA +/- 0.07 nA (P < 0.01 vs control, n = 5), from -0.32 nA +/- 0.08 nA to -0.27 nA +/- 0.08 nA (P < 0.01 vs control, n = 5). The inhibitory rate was 31% +/- 11%, 19% +/- 7%, respectively. The amplitude of ICRAC was dependent on extracellular Ca2+ concentration. The peak amplitude of ICRAC was -0.21 nA +/- 0.08 nA (n = 3) in Tyrode's solution with Ca2+ 1.8 mmol.L-1 (P < 0.01 vs the peak amplitude of ICRAC in external solution with Ca2+ 10 mmol.L-1).

Conclusion: The three calcium antagonists inhibited ICRAC effectively and protected hepatocytes from calcium overload via the inhibition of ICRAC.

Aim: To study the tissue distribution and its mechanism of a new recombinant tumor necrosis factor alpha derivative (rhTNF alpha Da) in mice.

Methods: 125I-rhTNF alpha Da was prepared by Iodogen method. Tissue distribution of 125I-rhTNF alpha Da in mice was studied by determining radioactivity of tetrachloroacetic acid (TCA)- precipitable fraction in tissues. The isolated heart-lung perfusion study using 125I-rhTNF alpha Da perfusate was carried out to study the distribution characteristics of 125I-rhTNF alpha Da in lung.

Results: Except for thyroid, AUC of the TCA-precipitable 125I-rhTNF alpha Da in tissues was highest in lung, which was 12.2-fold of that in serum, while concentrations in other tissues were all lower than that in serum. Perfusion study in vitro revealed that the concentration of radio-labeled peptide in lung was higher than that in perfusate. On the contrary, level in heart was much lower than that in perfusate. The overall distribution of 125I-rhTNF alpha Da in lungs showed rapidly equilibratory, dose-dependent, saturable, competitive, and highly affinitive, with Kd 47.6 pmol.L-1 and Bmax 348 fmol.g-1 (lung tissue).

Conclusion: The specific distribution of rhTNF alpha Da in lungs was its distinctive characteristics.

Aim: To study the pharmacokinetics of atenolol (Ate) stereoisomers in Chinese.

Method: A single oral dose of 100 mg of racemic Ate tablets were given to 12 healthy volunteers of Han nationality. Plasma and urine concentrations were determined by the reversed phase HPLC method.

Results: The disposition of d-Ate and l-Ate was conformed to one-compartment model. Maximal plasma concentration (Cmax): l-Ate (331 +/- 79) micrograms.L-1, d-Ate (342 +/- 78) micrograms.L-1. Area under blood concentration-time curve (AUC): d-Ate (2635 +/- 610) micrograms.h.L-1, l-Ate (2442 +/- 588) micrograms.h.L-1. Renal clearance (Clr): l-Ate (6.9 +/- 1.2) L.h-1, d-Ate (6.5 +/- 1.3) L.h-1.

Conclusion: The disposition of Ate stereoisomers is of stereoselectivity.

Aim: To study the influence of protopine (Pro) on the cytoplasmic free Ca2+ concentration ([Ca2+]i) in rabbit platelets.

Methods: Measurement of [Ca2+]i of platelets in vitro by Fura 2-AM fluorescence technique.

Results: In the presence of CaCl2 1 mmol.L-1, Pro 10, 20, and 40 mumol.L-1 attenuated the rise in [Ca2+]i evoked by ADP from (420 +/- 57) to (320 +/- 26), (264 +/- 21), and (180 +/- 14) nmol.L-1, respectively, by arachidonic acid (AA) from (280 +/- 36) to (210 +/- 17), (184 +/- 21), and (143 +/- 16) nmol.L-1, respectively, and by platelet-activating factor (PAF) from (350 +/- 42) to (282 +/- 31), (223 +/- 30), and (165 +/- 15) nmol.L-1, respectively. In the presence of egtazic acid 1 mmol.L-1, Pro 10, 20, and 40 mumol.L-1 reduced the Ca2+ release induced by ADP, AA, and PAF, respectively. Pro 10, 20, and 40 mumol.L-1 also decreased ADP-, AA-, and PAF-induced Ca2+ influx.

Conclusion: Pro inhibited not only Ca2+ release but also the influx of Ca2+.