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Titolo:
SOMATOSTATIN RECEPTORS IN THE RHESUS-MONKEY BRAIN - LOCALIZATION AND PHARMACOLOGICAL CHARACTERIZATION
Autore:
THOSS VS; PIWKO C; HOYER D;
Indirizzi:
SANDOZ PHARMA LTD,PRECLIN RES CH-4002 BASEL SWITZERLAND SANDOZ PHARMA LTD,PRECLIN RES CH-4002 BASEL SWITZERLAND
Titolo Testata:
Naunyn-Schmiedeberg's archives of pharmacology
fascicolo: 6, volume: 353, anno: 1996,
pagine: 648 - 660
SICI:
0028-1298(1996)353:6<648:SRITRB>2.0.ZU;2-B
Fonte:
ISI
Lingua:
ENG
Soggetto:
CENTRAL NERVOUS-SYSTEM; HIGH-AFFINITY BINDING; H-3 SOMATOSTATIN; CORTEX; RAT; SITES; AUTORADIOGRAPHY; SUBPOPULATIONS; PITUITARY; TISSUE;
Keywords:
SOMATOSTATIN (SRIF); RHESUS MONKEY BRAIN; SRIF-1 RECEPTORS (SST(2), SST(3), SST(5)); SRIF-2 RECEPTORS (SST(1), SST(4));
Tipo documento:
Article
Natura:
Periodico
Settore Disciplinare:
Science Citation Index Expanded
Citazioni:
47
Recensione:
Indirizzi per estratti:
Citazione:
V.S. Thoss et al., "SOMATOSTATIN RECEPTORS IN THE RHESUS-MONKEY BRAIN - LOCALIZATION AND PHARMACOLOGICAL CHARACTERIZATION", Naunyn-Schmiedeberg's archives of pharmacology, 353(6), 1996, pp. 648-660

Abstract

To characterize the nature and distribution of somatostatin (SRIF) receptors, radioligand binding studies and in vitro receptor autoradiography were performed in Rhesus monkey brain using either [I-125]LTT-SRIF-28 ([Leu(8), D-Trp(22), I-125-Tyr(25)]SRIF-28) alone or in the presence of 3 nM seglitide (to block sst(2) sites), [I-125]Tyr(3)-octreotide or [I-125]CGP 23996 (c[Asu-Lys-Asn-Phe-Phe-Trp-Lys-Thr-Tyr-Thr-Ser])in buffer containing either 120 mM Na+ or 5 mM Mg2+. [I-125]Tyr(3)-octreotide labelled an apparently homogeneous population of sites in cerebral and cerebellar cortex (B-max = 27.3+/-2.8 fmol/mg protein and 52.6+/-8.6 fmol/mg protein, pK(d) = 9.46+/-0.03 and 9.93+/-0.03, respectively). The pharmacological profile of these sites correlated highly significantly with that of human recombinant sst(2) receptors (r = 0.996), but not or much less with that of human recombinant sst(3) and sst(5) receptors (r = 0.12 and 0.45, respectively). [I-125]CGP 23996 (in Na+-buffer) also labelled an apparently homogeneous population of sites in Rhesus monkey cerebral cortex membranes (B-max = 3.1+/-0.3 fmol/mg protein, pK(d) = 10.57+/-0.08), the pharmacological profile of whichwas highly significantly correlated with the profiles of human recombinant sst(1) and sst(4) receptors (r = 0.98 and 0.96, respectively). Using receptor autoradiography, high levels of [I-125]LTT-SRIF-28 and [I-125]Tyr(3)-octreotide recognition sites were found in basal ganglia,molecular and granular layers of the cerebellum and layers LII, V andVI of entorhinal cortex. In these regions, the addition of 3 nM seglitide produced a marked decrease of [I-125]LTT-SRIF-28 binding. Low levels of [I-125]LTT-SRIF-28 binding were observed in subiculum, pituitary and choroid plexus. By contrast, [I-125]CGP 23996 labelling in the presence of Mg2+ as well as Na+ ions was highest in pituitary and choroid plexus. However, [I-125]CGP 23996 binding was diversely affected bythese ionic conditions in several regions of hippocampus and cerebralcortex. Displacement of [I-125]CGP 23996 (in Mg2+-buffer) with seglitide in the molecular layer of the cerebellum, deep layers of the entorhinal cortex, layers I, II and V of the insular cortex and frontal pole yielded complex competition curves suggesting the presence of two populations of SRIF receptors. By contrast, [I-125]CGP 23996 binding (inMg2+-buffer) in the choroid plexus, hilus of the dentate gyrus and stratum oriens and radiatum of the CA3field of hippocampus was not affected by seglitide up to 10 mu M, suggesting only sst(1) and/or sst(4) sites which have a negligible affinity for seglitide to be present in these structures. Taken together, these results suggest that [I-125]CGP23996 (in the presence of Na+) labels exclusively SRIF-2 receptors (sst(1) and/or sst(4)), whereas in the presence of Mg2+ ions, [I-125]CGP23996 labels both SRIF-2 and SRIF-1 receptors (sst(2), sst(3) and sst(5)) The present study also demonstrates the presence and differentialdistribution of sst(2) and sst(1)/sst(4) receptors in the Rhesus monkey brain.

ASDD Area Sistemi Dipartimentali e Documentali, Università di Bologna, Catalogo delle riviste ed altri periodici
Documento generato il 03/04/20 alle ore 09:53:53