Evidence for a role of nitric oxide in hindlimb vasodilation induced by hypothalamic stimulation in anesthetized rats
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| Format: | Artículo científico |
| Sprache: | en |
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Academia Brasileira de Ciências
2005
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| _version_ | 1876434396231237632 |
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| author | Marcos L. Ferreira-Neto |
| author_facet | Marcos L. Ferreira-Neto |
| contents | Evidence for a role of nitric oxide in hindlimb vasodilation induced by hypothalamic stimulation in anesthetized rats Marcos L. Ferreira-Neto Olga S. Possas Oswaldo U. Lopes Sérgio L. Cravo Multidisciplinaria (Ciencias Naturales y Exactas) ow hypothalamus defensereaction hindlimbbloodfl electricalstimulation Electricalstimulationofthehypothalamusproducescardiovascularadjustmentsconsistingofhypertension,tachycardia,visceralvasoconstrictionandhindlimbvasodilation.Previousstudieshavedemonstratedthathindlimbvasodilationisdueareductionofsympatheticvasoconstrictortoneandtoactivationofβ2-adrenergicreceptorsbycatecholaminerelease.However,theexistenceofayetunidentifiedvasodilatormechanismhasalsobeenproposed.Recentstudieshavesuggestedthatnitricoxide(NO)maybeinvolved.TheaimofthepresentstudywastoinvestigatetheroleofNOinthehindquartervasodilationinresponsetohypothalamicstimulation.Inpentobarbital-anesthetizedratshypothalamicstimulation(100Hz,150µA,6s)producedhypertension,tachycardia,hindquartervasodilationandmesentericvasoconstriction.Alpha-adrenoceptorblockadewithphentolamine(1.5mg/kg,iv)plusbilateraladrenalectomydidnotmodifyhypertension,tachy-cardiaormesentericvasoconstrictioninducedbyhypothalamicstimulation.Hindquartervasodilationwasstronglyreducedbutnotabolished.TheremainingvasodilationwascompletelyabolishedafterivinjectionoftheNOSinhibitorL-NAME(20mg/kg,iv).ToproperlyevaluatetheroleofthemechanismofNOinhindquartervasodilation,inasecondgroupofanimalsL-NAMEwasadministeredbeforeα-adrenoceptorblockadeplusadrenalectomy.L-NAMEtreatmentstronglyreducedhindquartervasodilationinmagnitudeandduration.TheseresultssuggestthatNOisinvolvedinthehindquartervasodilationproducedbyhypotha-lamicstimulation. 2005 artículo científico 0001-3765 https://www.redalyc.org/articulo.oa?id=32777205 en http://www.redalyc.org/revista.oa?id=327 Anais da Academia Brasileira de Ciências application/pdf Academia Brasileira de Ciências Anais da Academia Brasileira de Ciências (Brasil) Num.2 Vol.77 |
| format | Artículo científico |
| id | redalyc_32777205 |
| institution | Redalyc |
| language | en |
| publishDate | 2005 |
| publisher | Academia Brasileira de Ciências |
| spellingShingle | Evidence for a role of nitric oxide in hindlimb vasodilation induced by hypothalamic stimulation in anesthetized rats Marcos L. Ferreira-Neto Multidisciplinaria (Ciencias Naturales y Exactas) ow hypothalamus defensereaction hindlimbbloodfl electricalstimulation Evidence for a role of nitric oxide in hindlimb vasodilation induced by hypothalamic stimulation in anesthetized rats Marcos L. Ferreira-Neto Olga S. Possas Oswaldo U. Lopes Sérgio L. Cravo Multidisciplinaria (Ciencias Naturales y Exactas) ow hypothalamus defensereaction hindlimbbloodfl electricalstimulation Electricalstimulationofthehypothalamusproducescardiovascularadjustmentsconsistingofhypertension,tachycardia,visceralvasoconstrictionandhindlimbvasodilation.Previousstudieshavedemonstratedthathindlimbvasodilationisdueareductionofsympatheticvasoconstrictortoneandtoactivationofβ2-adrenergicreceptorsbycatecholaminerelease.However,theexistenceofayetunidentifiedvasodilatormechanismhasalsobeenproposed.Recentstudieshavesuggestedthatnitricoxide(NO)maybeinvolved.TheaimofthepresentstudywastoinvestigatetheroleofNOinthehindquartervasodilationinresponsetohypothalamicstimulation.Inpentobarbital-anesthetizedratshypothalamicstimulation(100Hz,150µA,6s)producedhypertension,tachycardia,hindquartervasodilationandmesentericvasoconstriction.Alpha-adrenoceptorblockadewithphentolamine(1.5mg/kg,iv)plusbilateraladrenalectomydidnotmodifyhypertension,tachy-cardiaormesentericvasoconstrictioninducedbyhypothalamicstimulation.Hindquartervasodilationwasstronglyreducedbutnotabolished.TheremainingvasodilationwascompletelyabolishedafterivinjectionoftheNOSinhibitorL-NAME(20mg/kg,iv).ToproperlyevaluatetheroleofthemechanismofNOinhindquartervasodilation,inasecondgroupofanimalsL-NAMEwasadministeredbeforeα-adrenoceptorblockadeplusadrenalectomy.L-NAMEtreatmentstronglyreducedhindquartervasodilationinmagnitudeandduration.TheseresultssuggestthatNOisinvolvedinthehindquartervasodilationproducedbyhypotha-lamicstimulation. 2005 artículo científico 0001-3765 https://www.redalyc.org/articulo.oa?id=32777205 en http://www.redalyc.org/revista.oa?id=327 Anais da Academia Brasileira de Ciências application/pdf Academia Brasileira de Ciências Anais da Academia Brasileira de Ciências (Brasil) Num.2 Vol.77 |
| title | Evidence for a role of nitric oxide in hindlimb vasodilation induced by hypothalamic stimulation in anesthetized rats |
| topic | Multidisciplinaria (Ciencias Naturales y Exactas) ow hypothalamus defensereaction hindlimbbloodfl electricalstimulation |
| url | https://www.redalyc.org/articulo.oa?id=32777205 |