RÉSUMÉ
Objective: To observe the effects of activation or blockade of the prelimbic (PrL) α1-adrenoceptors on anxiety-like behaviors and amygdaloid neural activities in rats with Parkinson's disease (PD). Methods: The rat model of PD was established by 6-hydroxydopamine (6-OHDA) unilateral lesion of the medial forebrain bundle (MFB). Then the anxiety-like behavior of rats was detected by the open field test. In addition, the changes of anxiety-like behavior, the effects of PrL α1-adrenoceptor stimulation on monoamines and c-Fos expression in the amygdala were also observed after local injection of the selective α1-adrenoceptor agonist or antagonist into the PrL by guided cannula. Results: Unilateral 6-OHDA lesions of the MFB in rats induced anxiety-like behaviors (P<0.001). Furthermore, activation of the PrL α1-adrenoceptors significantly induced or enhanced anxiety-like behaviors in the rats (sham group: P<0.001; lesion group: P<0.05), while blockade of the α1-adrenoceptors produced anxiolytic effects (sham group: P<0.001; lesion group: P<0.05). Then activation of the PrL α1-adrenoceptors increased the levels of DA and 5-HT while blockade of the PrL α1-adrenoceptors decreased DA and 5-HT levels in the amygdala in sham-operated rats (DA & 5-HT: P<0.001). However, compared to those of sham-operated rats, activation of the PrL α1-adrenoceptors increased the levels of NA and 5-HT while blockade of the PrL α1-adrenoceptors decreased NA and 5-HT levels in the amygdala in the lesioned rats (NA & 5-HT: P<0.001). In addition, the density of c-Fos immunoreactive positive neurons in the amygdala increased after intra-PrL injection α1-adrenoceptors agonist phenylephrine (sham group & lesion group: P<0.001). Conclusion: These findings indicate that changed neural activities in the amygdala after activation or blockade of the PrL α1-adrenoceptors are involved in regulating anxiety-like behaviors in PD rats.
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Aim To investigate the effects of mmLDL on the up-regulation ofα1 receptors in moues mesenter- ic arteries. Methods Mice tail intravenous injection of mmLDL was used . Vitro sensitive myograph was empl- oyed to examine Noradrenaline ( NA) induced vascular contraction on mice mesenteric artery, and the mRNA and protein expressions ofα1 andα2 receptors were an-alyzed by real-time PCR and Western blot, respective-ly. Results mmLDL significantly increased NA in-duced concentration-contractile curve, and the data of Emax and pEC50 were from ( 122. 61 ± 9. 40 )% and (5. 65 ± 0. 05 ) in normal saline ( NS ) group to (161. 01 ± 6. 90 )% and ( 6. 20 ± 0. 08 ) in mmLDL group (P tion-contractile curve induced by NA towards right. Af-ter using mmLDL, the mRNA and protein levels of α1 adrenoceptor were significantly increased, but the mR-NA and protein levels of α2 adrenoceptor were not changed. Conclusion Tail intravenous injection of mmLDL enhances the vascular expressions of α1 adre-noceptors and the contractile effects mediated byα1 ad-renoceptors.
RÉSUMÉ
Aim To analyze the blocking effect of ( ± ) doxazosin [ ( ± ) DOX ] , ( -) doxazosin [ ( -) DOX] and ( +) doxazosin [( +) DOX] on the vaso-constriction of rat isolated mesenteric arterioles media-ted by α1-adrenoceptors. Methods The vasoconstric-tion induced by phenylephrine ( Phe) in the rat isola-ted mesenteric arterioles ( the second- and third-order branches) was recorded using DMT wire myograph sys-tem 620M, and theα1-adrenoceptor antagonistic activ-ity of ( ± ) DOX and its enantiomers was analyzed. Results The inner diameter of second- and third-or-der branches of the rat mesenteric artery was (162. 5 ± 5. 3) μm (n=11) and (103. 1 ± 2. 3) μm (n=23), respectively. The values of normalized preload of the second-and third-order branches, which were calculat-ed by the LabChart software, were (2. 93 ± 0. 51) mN ( n =11 ) and ( 2. 64 ± 0. 50 ) mN ( n =23 ) ( P >0. 05 ) . Vasoconstrictive responses to Phe in the sec-ond-order branche of rat mesenteric artery under nor-malized preloads were not significantly different from those under 5 mN preload;however, the Emax values of the Phe-induced vasoconstriction under 10 mN, 15 mN and 20 mN preloads were decreased by 12%, 29%and 43% ( P<0. 01 ) respectively compared with those under normalized preload. The concentration-response curves for Phe were shifted to right in a concentration dependent manner by ( -) DOX or ( +) DOX at 0. 001 , 0. 01 and 0. 1 μmol · L-1 without significant change in their Emax values in the second-and third-or-der branches of rat mesenteric artery. Schild plot anal-ysis indicated that ( -) DOX, ( +) DOX and ( ± ) DOX non-competitively inhibited the vasoconstrictive responses to Phe in the second-order branches, and the rank order of pKB values was ( +) DOX ( 8. 67 ± 0. 10 ) , ( ± ) DOX ( 8. 53 ± 0. 090 ) , ( -) DOX (7. 85 ± 0. 09). However, schild plot analysis indica-ted that ( -) DOX and ( +) DOX competitively inhibi-ted the vasoconstrictive responses for Phe in the third-order branch, and the rank order of their pKB values was ( ± ) DOX ( 8. 68 ± 0. 17 ) , ( +) DOX ( 8. 48 ± 0. 10 ) , ( -) DOX ( 7. 48 ± 0. 140 ) . Conclusion The α1-adrenoceptor blocking activity of ( -) DOX is much weaker than that of ( +) DOX or ( ± ) DOX in the rat isolated mesenteric arterioles, and there is a tendency to enhance the activity of ( ± ) DOX in third-order branches of the rat mesenteric artery though theα1-adrenoceptor blockade effect of ( ± ) DOX is not significantly different from ( +) DOX.
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OBJECTIVE To investigate the blocking activities of a series of potential α1-adrenoceptor (α1-AR) antagonists (Compounds B1 -B9) on α1-AR.METHODS ① A series of potential α1-adrenoceptor (α1-AR) antagonists,indolylpiperidine derivative (IPD) and Compounds B1 -B9,with indolylpiperidine moiety and different substitutes were synthesized through the coupling of indolylpiperidine and piperazine derivatives.② Inotropic responses experiment was used to examine blocking effects of IPD and Compounds B1 - B9 in isolated rat atria by phenylephrine (PE) stimulation.③ Blocking effect of IPD and Compounds B1 - B9 on phosphorylation level of extracellular signal-regulated kinase (ERK) in PE treated HEK293 cells was tested by Western blotting.RESULTS ① Potential α1-adrenoceptor (α1-AR) antagonists with indolylpiperidine moiety and different substitutes were synthesized successfully.② PE caused a dose-dependent inotropic response which was inhibited by pre-incubation of phentolamine (Phen),a non-selective α1-AR antagonist,IPD and Compounds B1,B3,B4,B7,B8 and B9,respectively; IPD and Compounds B4 and B8 caused an obvious rightward shift of inotropic response-curve,the pA2 values for IPD and Compounds B4 and B8 were 6.72 ± 0.21,6.86 ± 0.29 and 6.67 ± 0.19,respectively.③ Phosphorylation level of ERK1/2 was inhibited by pre-incubation with Compounds B1,B2,B3,B5,B6,B7,B8 and B9 or IPD in PE treated α1A-AR stably expressed HEK293 cells; PE-stimulated phosphorylation level of ERK1/2 was inhibited by pre-incubation with Compounds B2,B4,B7 or B8 in α1B-AR stably expressed HEK293 cells.CONCLUSION Compound B4 has a selective blocking activity on α1B-AR,and Compounds B1,B3,B5,B6 and B9 or IPD have a selective blocking activity on the phosphorylation level of ERK1/2.
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Aim: To search for novel α_1-adrenoceptor(α_1-AR) antagonists. Methods: On the basis of hybridization principle with silodosin as the lead compound, twelve 5-[2-[4-[ ( substituted phenoxy) alkyl] piperazin-1-yl] propyl] indoline compounds were designed and synthesized by maintaining indoline while incorporating the 1-[(substituted phenoxy) alkyl] piperazine group. Results: The structures of synthesized target compounds were confirmed by the elemental analysis, IR, ESI-MS and ~1H NMR. Preliminary pharmacological test showed that pA_2 values of six target compounds were greater than 7. 50, which suggested that the compounds possessed considerable α_1-AR antagonic activity. Conclusion: 5-[2-[4-[ ( substituted phenoxy) alkyl] piperazin-1-yl] propyl] indoline compounds is potentially a new candidate for α_1-AR antagonist.