EXCITATORY NEUROTENSIN RECEPTORS ON THE SMOOTH-MUSCLE OF THE RAT FUNDUS - POSSIBLE IMPLICATIONS IN GASTRIC-MOTILITY

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dc.contributor.authorHUIDOBROTORO, JP
dc.contributor.authorKULLAK, A
dc.date.accessioned2025-01-23T19:27:42Z
dc.date.available2025-01-23T19:27:42Z
dc.date.issued1985
dc.description.abstractPicomolar concentrations of neurotensin caused concentration-dependent contractions of the longitudinal musculature of the fundus of the rat stomach. The EC50 [concentration giving 50% effectiveness] of neurotensin was .apprx. 1.5 nM. On a molar basis neurotensin was about 5-10 times more potent than 5-hydroxytryptamine (5-HT) and .apprx. 80 times as active as acetylcholine in producing similar contractions. Studies with structurally related peptides indicated that whereas the carboxy terminal portion of neurotensin was essential for biological activity, a substantial part of its amino terminus end could be removed without affecting its potency. The EC50 for the neurotensin fragment 8-13 was identical to that of neurotensin, its 1-8 or 1-11 fragments were completely inactive. Tetrodotoxin did not modify the potency of neurotensin or structurally related analogs suggesting that the neurotensin receptor is probably located on the smooth muscle membrane. In addition, the potency of neurotensin in contracting the fundus was not modified by pretreatment with atropine, methysergide or diphenhydramine. Fade to the contractile response of neurotensin was followed by the development of tachyphylaxis; densensitization was concentration-dependent and characterized by a shift in the agonist concentration-response curve to the right and downwards. Desensitization with a priming concentration of neurotensin (.apprx. EC50) caused a substantial blockade of its excitability. There was cross-densensitization between neurotensin and the contractile activity of neurotensin 8-13 or xenopsin, but not with angiotensin II, bradykinin, substance P, acethylcholine, 5-HT or histamine. Pretreatment of the fundus strip with verapamil 0.3-1 .mu.M antagonized in a concentration-dependent fashion the neurotensin-induced contractions but not the muscular contractions caused by acetylcholine. Neurotensin activates a specific excitatory receptor probably located on the cell membrane of the smooth muscles of the rat fundus. This receptor is somehow related to a voltage-dependent Ca channel, sensitive to verapamil.
dc.fuente.origenWOS
dc.identifier.eissn1476-5381
dc.identifier.issn0007-1188
dc.identifier.urihttps://repositorio.uc.cl/handle/11534/99758
dc.identifier.wosidWOS:A1985AFA6400013
dc.issue.numero4
dc.language.isoen
dc.pagina.final910
dc.pagina.inicio897
dc.revistaBritish journal of pharmacology
dc.rightsacceso restringido
dc.subject.ods03 Good Health and Well-being
dc.subject.odspa03 Salud y bienestar
dc.titleEXCITATORY NEUROTENSIN RECEPTORS ON THE SMOOTH-MUSCLE OF THE RAT FUNDUS - POSSIBLE IMPLICATIONS IN GASTRIC-MOTILITY
dc.typeartículo
dc.volumen84
sipa.indexWOS
sipa.trazabilidadWOS;2025-01-12
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