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Current Alzheimer Research 03/2006; 3(1):35-6. · 3.95 Impact Factor
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E Bignon,
A Bachy,
R Boigegrain,
R Brodin,
M Cottineau,
D Gully,
J M Herbert,
P Keane, C Labie,
J C Molimard, [......],
C Petereau,
V Prabonnaud,
M P Rockstroh,
P Schaeffer,
O Servant,
O Thurneyssen,
P Soubrié,
M Pascal,
J P Maffrand,
G Le Fur
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ABSTRACT: SR146131 inhibited the binding of [125I]-Bolton Hunter (BH)-sulfated cholecystokinin octapeptide (CCK-8S) for the human recombinant cholecystokinin subtype 1 (CCK1) receptor (IC50 = 0.56 nM) with high (300-fold) selectivity to the CCK2 receptor. The biological activity of SR146131 was characterized in vitro in a NIH-3T3 cell line expressing the human recombinant CCK1 receptor (3T3-hCCK1). Measuring intracellular calcium release, SR146131 behaved as a full agonist with an efficacy comparable with that of CCK-8S (EC50 = 1.38 +/- 0.06 nM). On individual cells, SR146131 induced, like CCK-8S, Ca2+ oscillations at subnanomolar concentrations and sustained responses at higher concentrations. Like CCK-8S, SR146131 also fully stimulated inositol monophosphate formation (EC50 = 18 +/- 4 nM). SR146131 partially activated mitogen-activated protein kinase and enhanced the expression of the immediate early gene krox 24. In the human CHP212 and IMR32 neuroblastoma cell lines, which constitutively express the CCK1 receptor, SR146131 behaved as a partial agonist on intracellular calcium release and inositol monophosphate formation. All of these effects of SR146131 were inhibited by the CCK1 receptor antagonists SR27897B and devazepide, suggesting that the effects of SR146131 were entirely mediated by the CCK1 receptor. In contrast, high concentrations (>1 microM) of SR146131 had only minimal effects on CCK-8S-stimulated and unstimulated Chinese hamster ovary (CHO) cells expressing the human CCK2 receptor, indicating that SR146131 is functionally inactive on the CCK2 receptor. In conclusion, these in vitro experiments show that SR146131 is a highly potent and selective agonist of the CCK1 receptor.
Journal of Pharmacology and Experimental Therapeutics 05/1999; 289(2):742-51. · 3.83 Impact Factor
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ABSTRACT: The present study investigated, in rats, whether blockade of cannabinoid CB1 receptors may alter Fos protein expression in a manner comparable to that observed with antipsychotic drugs. Intraperitoneal administration of the selective CB1 receptor antagonist, SR141716, dose-dependently (1.0, 3.0 and 10 mg/kg) increased Fos-like immunoreactivity in mesocorticolimbic areas (prefrontal cortex, ventrolateral septum, shell of the nucleus accumbens and dorsomedial caudate-putamen), while motor-related structures such as the core of the nucleus accumbens and the dorsolateral caudate-putamen were unaffected. In the ventrolateral septum, taken as a representative structure, the Fos-inducing effect of SR141716 (10 mg/kg) was maximal 2 h after injection and returned to near control levels by 4 h. Within the prefrontal cortex, SR141716 increased the number of Fos-positive cells predominantly in the infralimbic and prelimbic cortices, presumptive pyramidal cells being the major cell types in which Fos was induced. The D1-like receptor antagonist, SCH23390 (0.1 mg/kg), did not prevent the Fos-inducing effect of SR141716 in any brain region examined (prefrontal cortex, nucleus accumbens, ventrolateral septum and dorsomedial caudate-putamen), although SCH23390 significantly reduced Fos expression induced by cocaine (20 mg/kg) in all these regions. By contrast, the dopamine D2-like agonist, quinpirole (0.25 mg/ kg), counteracted SR141716-induced Fos-like immunoreactivity in the ventrolateral septum, the nucleus accumbens and the dorsomedial caudate-putamen, while no antagonism was observed in the prefrontal cortex. Microdialysis experiments in awake rats indicated that SR141716, at doses which increased Fos expression (3 and 10 mg/kg), did not alter dopamine release in the shell of the nucleus accumbens. Finally, SR141716 increased the levels of neurotensin-like immunoreactivity in the nucleus accumbens, but not in the caudate-putamen. Collectively, the present results show that blockade of cannabinoid receptors increases Fos- and neurotensin-like immunoreactivity with characteristics comparable to those reported for atypical neuroleptic drugs.
Neuroscience 02/1999; 91(2):607-20. · 3.38 Impact Factor
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ABSTRACT: The effects of SR 31742A, a specific sigma ligand, were investigated on neurotensin (NT) biosynthesis in the basal ganglia of the rat. Both single and repeated treatments with either SR 31742A (20 mg/kg i.p.) or haloperidol (1 mg/kg i.p.) increased the concentration of NT-like immunoreactivity (NT-li) in the nucleus accumbens. In contrast to haloperidol, the administration of SR 31742A failed to increase the concentration of NT-li in the caudate-putamen. We have further investigated drug-induced variations in NT biosynthesis by studying NT/neuromedin N (NT/NN) mRNA levels in the nucleus accumbens and the ventral tegmental area of the rat following SR 31742A administration. The NT/NN mRNA levels in the ventral tegmental area were increased by a maximum of fifteen fold (7 h at 20 mg/kg i.p.). A lower increase in NT/NN mRNA levels was elicited in the nucleus accumbens. These results suggest that the increase in NT-li observed after SR 31742A treatment, like that produced by haloperidol, may result from an increase of NT biosynthesis. Furthermore, the effects of SR 31742A on NT metabolism are similar to those of atypical antipsychotics, since they appear to be selective for the limbic system.
Synapse 05/1995; 19(4):241-6. · 2.94 Impact Factor
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ABSTRACT: The effects of SR 31742A, a specific sigma site ligand, were investigated on regional neurotensin concentrations in rat brain. Both acute and chronic (21-day) treatment with either SR 31742A (20 mg/kg i.p.) or haloperidol (1 mg/kg i.p.) increased the neurotensin-like immunoreactivity in the nucleus accumbens. In contrast to haloperidol, the administration of SR 31742A failed to increase the concentration of neurotensin-like immunoreactivity in the caudate-putamen. Thus, the effects of SR 31742A appear to be selective for the limbic system.
European Journal of Pharmacology 03/1993; 231(3):465-7. · 2.52 Impact Factor
