Linked Life Data

954843

Source:http://linkedlifedata.com/resource/pubmed/id/954843

Statements in which the resource exists as a subject.
PredicateObject
rdf:type
lifeskim:mentions
pubmed:issue
2
pubmed:dateCreated
1976-11-1
pubmed:abstractText
In anaesthetized dogs, clonidine (10 mug/kg i.v.) increased the spontaneous firing of the carotid sinus nerve and decreased blood pressure and heart rate. After transection of the spinal cord, clonidine decreased heart rate and this bradycardia was abolished by selective baroreceptor denervation. Clonidine (1 mug/kg) injected into the vertebral artery of anaesthetized dogs, pretreated with a beta-adrenoceptor blocking agent (S 2395: 50 mug/kg i.v.) potentiated the bradycardia induced by stimulation of the carotid sinus nerve but did not change the hypotension and bradycardia produced by stimulation of the nucleus tractus solitarius or of the nucleus ambiguus. In anaesthetized cats with bilateral destruction of nuclei tractus solitarii, clonidine (10 mug/kg i.v.) decreased blood pressure and heart rate. Clonidine (2 mug/kg), injected into the vertebral artery of anaesthetized dogs pretreated with a beta-adrenergic blocking agent (S 2395: 50 mug/kg i.v.) or guanethidine, induced a bradycardia but the discharges of the carotid sinus nerve were not increased. Selective baroreceptor denervation abolished this bradycardia. In conclusion, these experiments provide direct evidence that the central facilitory effect of clonidine on baroreceptor impulses play a role in the bradycardic effect of the drug. This facilitation is likely localized in the nucleus tractus solitarius at the first synapse of baroreceptor fibres. The vagally mediated bradycardia can be explained by an increase in baroreceptor discharges and by the central facilitation of baroreceptor impulses. The site of the hypotensive effect of clonidine did not seem to be localized in the nucleus tractus solitarius.
pubmed:language
eng
pubmed:journal
pubmed:citationSubset
IM
pubmed:chemical
pubmed:status
MEDLINE
pubmed:month
Aug
pubmed:issn
0014-2999
pubmed:author
pubmed:issnType
Print
pubmed:volume
38
pubmed:owner
NLM
pubmed:authorsComplete
Y
pubmed:pagination
293-303
pubmed:dateRevised
2003-11-14
pubmed:meshHeading
pubmed:year
1976
pubmed:articleTitle
Action of clonidine on the baroreceptor pathway and medullary sites mediating vagal bradycardia.
pubmed:publicationType
Journal Article