A highly selective NK-2 tachykinin receptor antagonist containing D-tryptophan

The classical approach used in the development of substance P (SP) antagonists, i.e. the introduction of multiple D-tryptophan (D-Trp), was successfully extended to neurokinin A (NKA). Thus, a new NK-2-selective tachykinin receptor antagonist, namely [Tyr5, D-Trp6,8,9, Arg10]NKA-(4-10), was developed that had pA2 values of 5.2, 7.9 and 4.9 in three monoreceptor in vitro assays for NK-1, NK-2 and NK-3 tachykinin receptors, respectively.     

The NK-1 receptor antagonist aprepitant as a broad spectrum antitumor drug

Aprepitant is a selective high-affinity antagonist of human substance P (SP)/Neurokinin-1 (NK-1) receptors. Until now this drug has been used as anxiolytic, antidepressant and antiemetic. It has been demonstrated that SP induces cell proliferation and NK-1 receptor antagonists different to aprepitant inhibit growth in several human cancer cell lines, where NK-1 receptors are overexpressed. The purpose of this study is to demonstrate the antitumor action of aprepitant. We performed an in vitro study of the growth inhibition capacity of the NK-1 receptor antagonist aprepitant against glioma, neuroblastoma, retinoblastoma and pancreas, larynx, gastric and colon carcinomas cell lines. Coulter counter was used to determine viable cell numbers followed by application of the MTS colorimetric method. Furthermore, a DAPI method was applied to demonstrate apoptosis. We have demonstrated: aprepitant at (5–70 μM) concentration elicits growth cell inhibition in a concentration dependent manner in all tumor cell line studied. Maximum inhibition (100%) was observed when the aprepitant was administered at a concentration of ≥70 μM in all tumor cell lines studied. The specific antitumor action of aprepitant occurs through the NK-1 receptor and tumor cells death was by apoptosis pathway. These findings reported here for the first time indicate that aprepitant is a new and promising broad spectrum antitumor drug in the treatment of cancer.     

The 5-HT2 receptor antagonist, MDL 28,133A, disrupts the serotonergic-dopaminergic interaction mediating the neurochemical effects of 3,4-methylenedioxymethamphetamine

The selective 5-HT₂ receptor antagonist MDL 28,133A dose dependently blocked the long-term deficits in rat brain 5-HT concentrations produced by the substituted amphetamine analogue 3,4-methylenedioxymethamphctamine (MDMA). This protective effect of MDL 28,133A could be abolished by coadministration of the dopamine precursor, L-dihydroxyphenylalanine (L-DOPA). Electrophysiological experiments demonstrated that the ability of MDL 28,133A to block the MDMA-induced slowing of A⁹ dopaminergic neurons was also sensitive to L-DOPA administration. Both sets of experiments suggest an interaction of MDL 28,133A at the level of dopamine synthesis. Consistent with this explanation, MDL 28,133A antagonized the MDMA-induced stimulation of dopamine synthesis in vivo. MDMA-induced 5-HT release did not reduce the firing rate of dopaminergic neurons as assessed by dopamine depletion following synthesis inhibition with α-mcthyl-p-tyrosinc (α-MPT). This indicates that the effect of 5-HT₂ receptor antagonists on MDMA-induced dopamine synthesis is not due simply to the removal of an inhibitory serotonergic input followed by an increase in dopamine cell firing and autoreceptor activation. MDL 28,133A was also shown to be without effect on the sensitivity of terminal dopamine autoreceptors. The results are consistent with the hypothesis that 5-HT₂ receptors are permissive for the stimulation of dopamine synthesis necessary to support MDMA-induced transmitter efflux.     

The 5-HT2 receptor antagonist, MDL 28,133A, disrupts the serotonergic-dopaminergic interaction mediating the neurochemical effects of 3,4-methylenedioxymethamphetamine.

The selective 5-HT₂ receptor antagonist MDL 28,133A dose dependently blocked the long-term deficits in rat brain 5-HT concentrations produced by the substituted amphetamine analogue 3,4-methylenedioxymethamphctamine (MDMA). This protective effect of MDL 28,133A could be abolished by coadministration of the dopamine precursor, L-dihydroxyphenylalanine (L-DOPA). Electrophysiological experiments demonstrated that the ability of MDL 28,133A to block the MDMA-induced slowing of A⁹ dopaminergic neurons was also sensitive to L-DOPA administration. Both sets of experiments suggest an interaction of MDL 28,133A at the level of dopamine synthesis. Consistent with this explanation, MDL 28,133A antagonized the MDMA-induced stimulation of dopamine synthesis in vivo. MDMA-induced 5-HT release did not reduce the firing rate of dopaminergic neurons as assessed by dopamine depletion following synthesis inhibition with -mcthyl-p-tyrosinc (-MPT). This indicates that the effect of 5-HT₂ receptor antagonists on MDMA-induced dopamine synthesis is not due simply to the removal of an inhibitory serotonergic input followed by an increase in dopamine cell firing and autoreceptor activation. MDL 28,133A was also shown to be without effect on the sensitivity of terminal dopamine autoreceptors. The results are consistent with the hypothesis that 5-HT₂ receptors are permissive for the stimulation of dopamine synthesis necessary to support MDMA-induced transmitter efflux.     

外周NK-1受体对甲醛致痛大鼠行为学的影响

目的探讨外周NK-1受体在甲醛致痛模型中的作用及可能的作用机制。方法24只雄性Wistar大鼠随机分为4组(n=6)。包括一个对照组:DMSO组和3个不同剂量的RP67580实验组:5 nmol组;20nmol组;100 nmol组。观察注射甲醛后各组大鼠行为学的改变。结果在甲醛致痛的第一、二时相,各实验组累积舔咬爪时间均短于对照组(P<0.05)。且在第二时相,各实验组之间差异有统计学意义(P<0.05),随着给药剂量增加,大鼠累积舔咬爪时间下降明显(P<0.05)。结论外周注射NK-1受体拮抗剂RP67580,对甲醛致痛模型的2个时相均有抗伤害作用,此作用可能与阻断P物质参与的伤害性信息传导有关。     

ZM 241385, an adenosine A(2A) receptor antagonist, inhibits hippocampal A(1) receptor responses

4-(2-[7-amino-2-(2-furyl?1,2,4?-triazolo?2,3a?-?1,3, 5?triazin-5-yl-amino]ethyl)phenol (ZM 241385) has been used as an antagonist of adenosine A(2A) receptors, exhibiting high selectivity over adenosine A(1) receptors. We now report that ZM 241385 (10-50 nM) attenuated the inhibitory action of N(6)-cyclopentyladenosine (10 nM) and R(-)-N(6)-phenylisopropyladenosine (R-PIA, 20 nM), two selective adenosine A(1) receptor agonists, on hippocampal population spike amplitude. This effect is unlikely to be a direct antagonism of adenosine A(1) receptor since the K(i) of ZM 241385 to displace [3H]PIA (2 nM) binding, from hippocampal membranes ranged from 0.8 to 1.9 microM. These results question the usefulness of ZM 241385 to define adenosine A(2A) receptors actions in functional studies.     

The selective serotonin(2A) receptor antagonist, MDL100,907, elicits a specific interoceptive cue in rats.

Employing a two-lever, food-reinforced, Fixed Ratio 10 drug discrimination procedure, rats were trained to recognize the highly-selective serotonin (5-HT)(2A) receptor antagonist, MDL100,907 (0.16 mg/kg, i.p.). They attained criterion after a mean +/- S.E.M. of 70 +/- 11 sessions. MDL100,907 fully generalized with an Effective Dose (ED)(50) of 0.005 mg/kg, s.c. A further selective 5-HT(2A) antagonist, SR46349, similarly generalized with an ED(50) of 0.04 mg/kg, s.c. In distinction, the selective 5-HT(2B) antagonist, SB204,741 (0.63 and 10.0 mg/kg), the 5-HT(2B/2C) antagonist, SB206,553 (0.16 and 2.5 mg/kg) and the selective 5-HT(2C) antagonists, SB242,084 (2.5 and 10.0 mg/kg,) and RS102221 (2.5 and 10.0 mg/kg), did not significantly generalize. In conclusion, selective blockade of 5-HT(2A) receptors by MDL100,907 elicits a discriminative stimulus in rats which appears to be specifically mediated via 5-HT(2A) as compared with 5-HT(2B) and 5-HT(2C) receptors.     

Intra-amygdala injection of the substance P [NK(1) receptor] antagonist L-760735 inhibits neonatal vocalisations in guinea-pigs.

The involvement of the basolateral amygdala in mediating the inhibition of neonatal vocalisation by substance P (NK(1) receptor) antagonists was examined. These studies determined whether the time course for separation-induced vocalisations in guinea-pig pups coincided with NK(1) receptor internalisation (a marker of substance P release) in the amygdala, and whether vocalisations could be blocked by focal injection of the NK(1) receptor antagonist L-760735 into this brain region. The peak period for neonatal vocalisations occurred 5-10 min following maternal separation. This coincided with the peak increase in the number of cells in the basolateral amygdala exhibiting NK(1) receptor endocytosis, consistent with the proposal that substance P is released in the amygdala as a result of isolation stress. Focal injection of L-760735 (15 nmol per side) but not L-770765 (an analogue of L-760735 which has low NK(1) receptor affinity) into the basolateral amygdala attenuated separation-induced vocalisations. In contrast, injection of L-760735 (15 nmol per side) into the dorsal ventricular nucleus of the thalamus, a region with relatively low density of NK(1) receptors, had no effect on neonatal vocalisations. These findings are consistent with other evidence that the amygdala is one possible site of action for the inhibition of neonatal vocalisations by substance P antagonists.     

Time and sex-dependent effects of an adenosine A2A/A1 receptor antagonist on motivation to self-administer cocaine in rats

Adenosine is an important neuromodulator, known to interact with both dopaminergic and glutamatergic systems to influence psychostimulant action. In the present study, we examined the effects of ATL444, a novel adenosine receptor antagonist, on motivation for cocaine in male and female rats. Adult male and female Sprague-Dawley rats were trained to self-administer cocaine (1.5 mg/kg/infusion) on a fixed-ratio 1 schedule with a daily maximum of 20 infusions. Following 5 consecutive sessions during which all 20 available infusions were obtained, motivation for cocaine (0.5 mg/kg/infusion) was assessed under a progressive ratio (PR) schedule, and once responding stabilized, the effect of treatment with ATL444 (0, 15, and 30 mg/kg, i.p.) was examined. As a control, we also assessed its effects on PR responding for sucrose. Binding studies revealed that ATL 444 was 3‐fold, 25-fold, and 400-fold more selective for the A2A receptor as compared to A1, A2B, and A3 receptors, respectively. ATL444 produced a significant increase in motivation for cocaine on the day of treatment in females with a trend for an increase in males. In addition, over the two PR sessions following ATL444 treatment a significant decrease in responding was observed in males but not females. Responding for sucrose was unaffected by ATL444 treatment. Our results reveal that adenosine receptor blockade may mediate both acute increases in the reinforcing effects of cocaine, and longer term inhibitory effects on cocaine reinforcement that differ according to sex.     

The NK1 receptor antagonist SR140333 inhibits capsaicin-induced ERK phosphorylation in sensory neurons

Primary sensory neurons respond to a vigorous excitation via the capsaicin receptor/TRPV1 cation channel by a phosphorylation of the Jak/STAT pathway as measured by phospho-STAT3, and of the Ras/Raf-MAPK pathway as measured by phospho-MAPK/ERK1/2. In the present investigation a possible involvement of NK1 receptors in the capsaicin-induced activation of these signal transduction pathways was investigated by protein extraction and Western immunoblotting. Phospho-MAPK/ERK1/2 and phospho-STAT3 were determined in the dorsal root ganglia (DRG) and in the sciatic nerve of rats at 3 and 6 h following a systemic capsaicin treatment without or with the pretreatment of the selective NK1 receptor antagonist SR140333 (1 mg/kg s.c.; 3 h before capsaicin). Capsaicin evoked a threefold increase in phospho-ERK in the sciatic nerve and a two- to threefold increase in the DRG at 3 h and 6 h after the treatment. SR140333 markedly attenuated the capsaicin-induced increase in phosphorylated ERK. In the sciatic nerve the difference was significant at each individual time point (3 and 6 h, p < 0.001). In the DRG the difference was significant when the data at 3 h and 6 h were combined (p < 0.05), but not when individual time points were considered. Capsaicin evoked a four- to fivefold increase in phospho-STAT3 in the sciatic nerve and a twofold increase in the DRG at 3 and 6 h after the treatment. SR140333 less markedly attenuated the capsaicin-induced increase in phosphorylated STAT3: whereas in the sciatic nerve the difference was significant when the data at 3 h and 6 h were combined (p < 0.05), no such treatment effect of SR140333 was observed in the DRG. The expression of TRPV1 mRNA, a specific marker of capsaicin-sensitive small sensory neurons, was investigated by RT-PCR 4 days after the capsaicin treatment. Treatment of rats with SR140333 had no influence on the long-term downregulation of TRPV1 mRNA by capsaicin. Based on the present results and previous findings it can be postulated that the capsaicin-induced ERK phosphorylation in sensory neurons is not a direct effect by capsaicin, but that rather substance P release from the stimulated sensory neurons with an NK1-mediated nerve growth factor (NGF) production is involved.     

The NK-1 receptor: a new target in cancer therapy

After binding to the specific neurokinin-1 (NK-1) receptor, the peptide substance P (SP), which is widely distributed in both the central and peripheral nervous systems, induces tumor cell proliferation, angiogenesis, and migration of the tumor cells for invasion and metastasis. However, after binding to NK-1 receptors, NK-1 receptor antagonists inhibit the three above mechanisms. In fact, the antiproliferative action exerted by NK-1 receptor antagonists is because they induce cancer cells to die by apoptosis, whereas SP exerts an antiapoptotic effect. Moreover, it is known that NK-1 receptors are overexpressed in tumors and that tumor cells express several isoforms of the NK-1 receptor. All these data suggest that the SP/NK-1 receptor system could play an important role in the development of cancer; that SP may be a universal mitogen in NK-1 receptor-expressing tumor cells, and that NK-1 receptor antagonists could offer a promising therapeutic strategy for the treatment of human cancer, since they act as broad-spectrum antitumor agents. In sum, the NK-1 receptor may be a new and promising target in the treatment of human cancer.     

Synthesis of new 4-heteroaryl-2-phenylquinolines and their pharmacological activity as NK-2/NK-3 receptor ligands

Substituted 4-heteroaryl-2-phenylquinolines were synthesized and tested on NK-2 and NK-3 receptors in order to get a better insight in the structure-activity relationship. On the whole, these molecules, which can be regarded as bioisosters of the NK-3 antagonist SB 218795, displayed a lower activity than the template. Ring electronic distribution and H-bond donor and acceptor positions played some role in selectivity, 2-imidazolyl substituted 2a showing affinity mainly towards NK-3 while 3-pyrazolyl substituted 4 displayed a preferential interaction with NK-2 receptor. Structural characterization of the synthesized compounds was achieved by NMR and mass techniques. Bidimensional 1H-NOESY experiments were a helpful tool for the assignment of the isomeric structures of compounds 9 and llb-c.     

In vivo pharmacology of irindalone,a 5-HT2 receptor antagonist with predominant peripheral effects

The in vivo effects of irindalone, a newly developed serotonin₂ (5-HT₂) antagonist, have been investigated in comparison with a series of reference compounds. Irindalone potently antagonizes the pressor response induced by 5-HT in pithed rats, but has a 173 times weaker effect against the α₁-adrenoceptor agonist phenylephrine. Irindalone is relatively weak in rat models detecting central 5-HT₂ antagonism, that is, inhibition of quipazine- or I-5-HTP plus citalopram-induced head twitches, inhibition of I-5-HTP plus citalopram-induced increases of flexor reflexes, and inhibition of the discriminative stimulus properties induced by d-LSD. Furthermore, it displaces in vivo ³H-ketanserin binding in frontal cortex. Irindalone weakly antagonizes the flexor reflex stimulated by the α₁-adrenoceptor agonist St 587. No dopamine receptor inhibition is detected in the methylphenidate gnawing test in mice. High bioavailability is indicated by the identical ED₅₀ values obtained in the head twitch model after s.c. and p.o. administration. The activity profile of irindalone resembles that of ketanserin except in two characteristics: ketanserin has greater potency than irindalone as an antagonist in the 5-HTP-induced flexor reflex, but has a shorter duration of action. The effect of irindalone is stereoselective, since its opposite enantiomer Lu 21-099 is almost inactive in the models for central and peripheral 5-HT₂ receptor antagonism. Finally, the effect of repeated treatment with irindalone (18 μmol/kg, p.o., twice daily for 2 weeks) on inhibition of quipazine-induced head twitches was studied. Two days after the last dose, the potency for inhibiting quipazine was unchanged, indicating that no tolerance to 5-HT₂ receptor antagonism develops using this dose regimen. It is concluded that irindalone is a potent 5-HT₂ antagonist with preferential effects at peripheral sites.     

The effects of metiamide and H1 receptor blocking agents on anaphylactic response in guinea-pigs.

The effects of metiamide and of four H1 receptor blocking agents (mepyramine, promethazine, clemastine and ketotifene) on anaphylactic reaction were studied in the guinea-pig. The H1 blockers conferred partial protection which shows that with the experimental protocol utilized (challenge injection with high doses of antigen), histamine plays a lesser role than other mediators released or synthesized. Metiamide (30.0 mg/kg i.v.) noticeably enhanced the increase in pulmonary resistance observed during anaphylactic reaction and reduced the protective effect of the H1 antagonists on this parameter and on histamine release. These effects might be explained by an inhibition - at least partial - of the negative feed-back mechanism through which histamine controls its own release, or by a specific action of metiamide in high doses. The transient tachycardia initially observed in anaphylactic shock is partly related to stimulation of cardiac H2 receptors by the histamine released, since it is suppressed by metiamide.     

Different effects of AT1 receptor antagonist and ET(A) receptor antagonist on ischemia-induced norepinephrine release in rat hearts

Angiotensin type 1 receptor (AT1R) antagonist and endothelin type A receptor (ET(A)R) antagonist were compared as regards their effects on ischemia-induced exocytotic or carrier-mediated norepinephrine (NE) release from cardiac sympathetic nerve endings. According to the Langendorff technique, isolated rat hearts were subjected to 20-minute or 40-minute global ischemia followed by 30-minute reperfusion. Candesartan (selective AT1R antagonist) and ABT-627 (selective ET(A)R antagonist) were perfused, beginning 15 minutes before ischemia. Candesartan (10 and 100 nM) and ABT-627 (3 μM) suppressed excessive NE overflow (exocytotic release) in the coronary effluent from the heart exposed to 20-minute ischemia. In addition, these agents improved postischemic cardiac dysfunction. On the other hand, the beneficial effects of ABT-627 (1 and 3 μM) on NE overflow (carrier-mediated release) and cardiac dysfunction were also observed in 40-minute ischemia, whereas those were not improved by treatment with candesartan (10 and 100 nM and 1 μM). These findings suggest that both AT1R antagonist and ET(A)R antagonist have ability to inhibit the exocytotic NE release, but the carrier-mediated NE release induced by prolonged ischemia cannot be avoided by AT1R antagonist. Thus, ET(A)R antagonist may be more useful than AT1R antagonist in the clinical settings of ischemic heart disease.     

Effect of hepatic or renal impairment on the pharmacokinetics of casopitant, a NK-1 receptor antagonist

Two studies were conducted in subjects with mild or moderate hepatic or renal impairment and subjects with normal organ function to evaluate the pharmacokinetics of casopitant and to assess its safety in these populations. A total of 26 subjects were enrolled in the hepatic impairment study and 18 subjects in the renal impairment study. All subjects received oral casopitant 100 mg once-daily for 5 days. Casopitant area under the concentration-time curve (AUC) increased 11% and 24% in subjects with mild or moderate hepatic impairment, respectively, on Day 1, compared with subjects with normal hepatic function; a similar increase was observed on Day 5. The AUC of the active major metabolite, GSK525060, was reduced 29% and 19% on Days 1 and 5, respectively, in subjects with moderate hepatic impairment, but not altered by mild hepatic impairment. Casopitant AUC increased 34% and 22% on Day 1 in subjects with mild or moderate renal impairment, respectively, and 28% and 11% on Day 5, respectively, compared with subjects with normal renal function. GSK525060 AUC was increased 17% and 24% on Days 1 and 5, respectively, in subjects with mild renal impairment; but did not significantly change in subjects with moderate renal impairment. Further age-adjusted analysis showed no meaningful effect of renal impairment on casopitant or GSK525060 AUC. Plasma protein binding of casopitant and GSK525060 was similar in all subjects. The pharmacokinetics of casopitant is not altered to a clinically significant extent in subjects with mild or moderate, hepatic or renal impairment. The impact of severe hepatic or renal impairment was not evaluated.     

腹腔注射5-HT_(2A)受体拮抗剂MDL11939对小鼠急性及慢性疼痛的影响

目的探讨5-羟色胺(5-hydroxytryptamine,5-HT)2A受体拮抗剂MDL11939在急性乙酸内脏痛、急性切口痛和坐骨神经慢性缩窄性损伤(chronic constrictive injury,CCI)模型中发挥的作用及意义。方法选用♂昆明小鼠,建立急性乙酸内脏痛、急性切口痛和CCI神经病理性痛模型,通过腹腔注射给药,观察乙酸致小鼠扭体反应次数变化、切口痛和CCI痛患侧热缩足反射潜伏期(thermal withdrawal latency,TWL)变化。结果在小鼠急性乙酸内脏痛模型中,与溶剂对照组相比,MDL11939(0.25、0.5、1.0 mg·kg~(-1),i.p.)呈剂量依赖性地减轻乙酸内脏痛,扭体反应次数明显减少。在急性切口痛和CCI模型中,与模型组和自身给药前相比,MDL11939(0.5 mg·kg~(-1),i.p.)可以明显提高小鼠患侧的热缩足阈值,减轻疼痛。结论 MDL11939通过腹腔系统性给药可以有效地减轻急性乙酸内脏痛、急性切口痛和CCI慢性神经病理性痛。     

The substance P (NK1) receptor antagonist L-760735 inhibits fear conditioning in gerbils

The ability of the substance P (NK(1) receptor) antagonist (SPA) L-760735 to inhibit conditioned fear was assessed in gerbils using a four plate apparatus. Animals that had been treated with diazepam (3 mg/kg) or L-760735 (3 mg/kg) 30 min before a 3 min conditioning session in the apparatus exhibited a release of plate crossings during the retest session approximately 3 h later. Plate crossings were also increased when animals received diazepam or L-760735 30 min before the retest session. In contrast, fluoxetine and venlafaxine (30 mg/kg) did not exhibit anxiolytic-like effects. During the retest session, gerbils drummed their hind feet on the floor; this behaviour was not observed spontaneously in gerbils that were na?ve to the apparatus. Foot drumming was abolished by pretreatment with L-760735 or diazepam (3 mg/kg) but was markedly increased following administration of fluoxetine or venlafaxine (30 mg/kg). Foot drumming elicited by aversive conditioning alone or in combination with fluoxetine was abolished by administration of L-760735 and by amygdala lesions involving the basolateral and lateral nuclei, indicating that this behaviour is an alarm signal or fear response mediated via release of substance P in brain circuits involving the amygdala. The observations provide further evidence for an anxiolytic-like profile of SPAs in preclinical assays and demonstrate a clear difference between the actions of SPAs and established antidepressant drugs.     

The GABA(A) receptor antagonist picrotoxin inhibits 5-hydroxytryptamine type 3A receptors

For a number of years it has been known that the CNS convulsant picrotoxin inhibits the GABA(A) receptor, an anion-selective member of the ligand-gated ion channel (LGIC) superfamily. PTX also inhibits other anion-selective LGIC members, such as GABA(C), glycine and glutamate-gated Cl(-) channels. In the present report, we tested the ability of picrotoxin to inhibit cation-selective 5-HT(3A) receptors. Murine 5-HT(3A) receptors were expressed in HEK293 cells, and functionally evaluated using whole-cell patch clamp recording. Picrotoxin inhibited 5-HT-gated currents in a concentration-dependent manner, with an IC(50) of approximately 30 microM. Moreover, the blockade by PTX was non-competitive and use-facilitated. Pentylenetetrazole and U-93631, ligands that act at a domain similar to that of picrotoxin in GABA(A) receptors, also inhibited the 5-HT(3A) receptor. For each ligand tested, its potency was 5-10 fold lower than typically observed in GABA(A) receptors. Our results demonstrate that, in addition to being a relatively non-selective inhibitor of anionic LGICs, picrotoxin also inhibits the cation-selective 5-HT(3A) receptor. Moreover, the fact that both PTZ and U-93631 similarly inhibit the 5-HT(3A) receptor is consistent with the suggestion that the site of picrotoxin action in this receptor may be comparable to that in anion-selective LGICs.     

内皮素及其受体拮抗剂对纤溶系统的影响

目的 探讨内皮素1(ET-1)及其受体拮抗剂(PD142893)对纤溶系统的影响。方法培养肺静脉内皮细胞株(ECV304),分为ET-1刺激组,培养基中加ET-1至终浓度为5、10、20、50、100nmol/L;PD142893干预组,培养基中加ET-1(100nmol/L)后加入PD142893,终浓度为10、100、200、400mol/L,24小时后测定上清中的组织纤溶酶原激活物(t-PA)和纤溶酶原激活物抑制剂-1(PAI-1)的含量。结果 空白对照组PAI-1含量为78.169±1.211ng/ml,ET-1(5、10、20、50、100nmol/L)刺激组分别为66.525±1.746、68.075±1.889、66.911±0.933、67.825±3.564、67.851±2.437ng/ml,刺激组与对照组之间存在显著差异,P<0.05;而两组t-PA含量无明显差异,P>0.05。无PD142893干预的ET-1(100nmol/L)组PAI-1含量为67.951±2.437ng/ml;ET-1(100nmol/L)+PD142893(10、100、200、400nmol/L)干预组PAI-1含量分别为91.112±8.811、99.311±14.079、113.467±7.679、114.933±9.623ng/ml,两者之间存在明显差异,P<0.05;而两组间t-PA含量无明显差异,P>0.05。结论 ET-1对肺静脉内皮细胞分泌的PAI-1有显著的抑制作用,而对t-PA无显著影响;用PD142893干预后,PAI-1显著升高,t-PA的含量无明显的改变。