0000000000009997
AUTHOR
Emmanuel Naline
showing 10 related works from this author
The nicardipine-isoprenaline interaction in human and guinea-pig isolated airways
1994
Summary— The effects of the dihydropyridine calcium antagonist nicardipine on the concentration-response curves of relaxant compounds acting through the adenylate-cyclase/cAMP system (isoprenaline, forskolin, adenosine and theophylline) or by the cGMP pathway (sodium nitroprusside) were studied on human isolated bronchus and guinea-pig isolated trachea. These effects were compared with those of nifedipine (a dihydropyridine derivative) and theophylline (a non-selective phosphodiesterase inhibitor). Nicardipine, in the range of 0.01 to 1 μM, significantly potentiated the relaxant effects of isoprenaline, forskolin, adenosine and theophylline, whereas the effects of sodium nitroprusside were …
Muscarinic M2 receptors in acetylcholine-isoproterenol functional antagonism in human isolated bronchus
2002
The muscarinic functional antagonism of isoproterenol relaxation and the contribution of muscarinic M2 receptors were examined in human isolated bronchus. In intact tissues, acetylcholine (ACh) precontraction decreased isoproterenol potency and maximal relaxation (−log EC50 shift = −1.49 ± 0.16 and Emax inhibition for 100 μM ACh = 30%) more than the same levels of histamine contraction. The M2receptor-selective antagonist methoctramine (1 μM) reduced this antagonism in ACh- but not histamine-contracted tissues. Similar results were obtained for forskolin-induced relaxation. After selective inactivation of M3 receptors with 4-diphenylacetoxy- N-(2-chloroethyl)piperadine hydrochloric acid (3…
Functional, biochemical and morphological studies on human bronchi after cryopreservation
1995
1. Human isolated bronchi have been investigated as fresh tissue or after storage (7 and 30 days) at -196 degrees C in foetal calf serum containing 1.8 M dimethyl sulphoxide. 2. After cryopreservation, the maximal contractile response to acetylcholine (3 mM) was reduced (approximately 25%) but the difference did not reach significance statistically. Maximal responses to other spasmogens tested (histamine, [Nle10]NKA(4-10), bradykinin, leukotriene D4, U46619, and KCl) did not differ between unfrozen and frozen/thawed tissues. The sensitivity of cryopreserved tissues to the constrictor agents tested was similar to that of fresh tissues. 3. The accumulation of inositol phosphates produced by a…
The human near-term myometrialβ3-adrenoceptor but not theβ2-adrenoceptor is resistant to desensitisation after sustained agonist stimulation
2004
1. In order to compare the beta(2)- and beta(3)-adrenoceptor (beta-AR) desensitisation process in human near-term myometrium, we examined the influence of a pretreatment of myometrial strips with either a beta(2)- or a beta(3)-AR agonist (salbutamol or SR 59119A, respectively, both at 10 microm, for 5 and 15 h) on the relaxation and the cyclic adenosine monophosphate (cAMP) production induced by these agonists. 2. To assess some of the mechanisms potentially implicated in the beta-AR desensitisation process, we studied the influence of such treatment on the number of beta(2)- and beta(3)-AR binding sites, the beta(2)- and beta(3)-AR transcripts expression and the phosphodiesterase 4 (PDE4) …
Calcium dependence of the contraction produced by endothelin (ET-1) in isolated guinea-pig trachea.
1990
Endothelin (ET-1, 1 pM to 0.1 microM) produced a concentration-dependent contraction of isolated guinea-pig trachea. BAY K 8644 (1 microM) did not significantly alter the concentration-response curve for ET-1. Incubation with nicardipine (10 microM) partly inhibited responses to low concentrations (10 pM to 1 nM) of ET-1 while verapamil (10 microM) and diltiazem (10 microM) were ineffective. La3+ (10 microM) and Cd2+ (10 microM) preferentially depressed the responses evoked by high concentrations (30 nM-0.1 microM) of ET-1 without affecting the responses evoked by low concentrations of the peptide. Incubation in Ca2(+)-free (with EDTA, 1 mM) medium resulted in suppression of the responses e…
Functional, biochemical and molecular biological evidence for a possible β3-adrenoceptor in human near-term myometrium
2000
The possible existence of a β3-adrenoceptor (β3-AR) in human near-term myometrium was investigated by in vitro functional and biochemical studies and analysis of mRNA expression. SR 59119A and SR 59104A and CGP 12177 (two selective agonists and a partial agonist, respectively, of the β3-AR), salbutamol and terbutaline (β2-AR agonists) each produced a concentration-dependent relaxation of the myometrial spontaneous contractions. There were no differences in pD2 values for the relaxing potencies of terbutaline, salbutamol, CGP 12177 and SR 59119A. The rank order for their relaxing efficacies was SR 59119A>SR 59104A>terbutaline∼salbutamol∼CGP 12177 (Emax=52±7%, 42±12% and ∼ 30% respectively). …
Is the beta3-adrenoceptor (ADRB3) a potential target for uterorelaxant drugs?
2007
International audience; The management of premature birth still remains unsatisfactory. Since the relative lack of efficiency and/or safety of current tocolytic agents have been highlighted, it is necessary to develop new uterorelaxant drugs deprived of important maternal and foetal side effects. Our work reported in this review focuses on a potential new target for tocolytic drugs, the beta3-adrenoceptor (ADRB3). This third type of ADRB is shown to be present and functional in human myometrium. We demonstrated that ADRB3 agonists are able to inhibit in-vitro spontaneous contractions of myometrial strips, via a cyclic AMP-mediated pathway. Furthermore, we established that ADRB3 is the predo…
Effects of ouabain on human bronchial muscle in vitro
2003
The effects of ouabain, an inhibitor of the plasmalemmal Na(+)/K(+)-ATPase activity, were examined in human isolated bronchus. Ouabain produced concentration-dependent contraction with -logEC(50)=7.16+/-0.11 and maximal effect of 67+/-4% of the response to acetylcholine (1 mM). Ouabain (10 microM)-induced contraction was epithelium-independent and was not depressed by inhibitors of cyclooxygenase and lipoxygenase, antagonists of muscarinic, histamine H(1)-receptors and alpha-adrenoceptors, or neuronal Na(+) channel blockade. The inhibition of ouabain contraction in tissues bathed in K(+)-free medium, and the inhibition by ouabain of the K(+)-induced relaxation confirm that the contractile a…
The effect of S-(+)-boldine on the α1-adrenoceptor of the guinea-pig aorta
1996
1. The cardiovascular activity of S-(+)-boldine, an aporphine alkaloid structurally related to papaverine, was determined. The work includes functional studies on guinea-pig isolated aorta contracted with noradrenaline, caffeine, KCl or Ca2+, and on guinea-pig trachea contracted with acetylcholine or histamine. 2. S-(+)-boldine inhibited in a concentration-dependent manner the contractile response evoked by noradrenaline (10 microM) in guinea-pig aorta (IC50 = 1.4 +/- 0.2 microM) while the KCl depolarizing solution (60 mM)- or the Ca2+ (1 mM)-induced contractions were only partially affected by boldine up to 300 microM. In contrast, papaverine relaxed noradrenaline (NA), KCl or Ca2+ induced…
The human near-term myometrial beta 3-adrenoceptor but not the beta 2-adrenoceptor is resistant to desensitisation after sustained agonist stimulatio…
2004
International audience; 1. In order to compare the beta(2)- and beta(3)-adrenoceptor (beta-AR) desensitisation process in human near-term myometrium, we examined the influence of a pretreatment of myometrial strips with either a beta(2)- or a beta(3)-AR agonist (salbutamol or SR 59119A, respectively, both at 10 microm, for 5 and 15 h) on the relaxation and the cyclic adenosine monophosphate (cAMP) production induced by these agonists. 2. To assess some of the mechanisms potentially implicated in the beta-AR desensitisation process, we studied the influence of such treatment on the number of beta(2)- and beta(3)-AR binding sites, the beta(2)- and beta(3)-AR transcripts expression and the pho…