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PredicateObject
rdf:type
lifeskim:mentions
pubmed:issue
2
pubmed:dateCreated
1991-9-20
pubmed:abstractText
We sought to determine the site of action and receptor type responsible for the antihypertensive actions of rilmenidine, an oxazoline analogue of clonidine. In anesthetized paralyzed rats decerebration did not alter the dose dependent reductions in arterial pressure and heart rate elicited by i.v. drug. Rilmenidine microinjected bilaterally into the C1 area of the rostral ventrolateral medulla (RVL), but not nucleus tractus solitarii (NTS) nor caudal ventrolateral medulla (CVL), elicited dose-dependent falls in arterial pressure and heart rate at doses an order of magnitude less than required systemically. Prior microinjection into the C1 area of the selective alpha 2-adrenoceptor antagonist SKF-86466, even at high doses, failed to modify the hypotension to i.v. rilmenidine. However, microinjection of 3- to 10-fold lower doses of idazoxan, a ligand for imidazole as well as alpha 2-adrenoceptors, blocked the effects. Rilmenidine also competed with the clonidine analogue [3H]p-aminoclonidine ([3H]PAC) at specific binding sites in membranes of bovine ventrolateral medulla and frontal cortex. In RVL rilmenidine competed with binding to imidazole and alpha 2-adrenergic binding sites with a 30-fold selectivity for the imidazole binding sites. In frontal cortex binding was of lower affinity and restricted to alpha 2-adrenergic sites. We conclude that rilmenidine, like clonidine, acts to lower arterial pressure by an action on imidazole receptors in the C1 area of RVL. The higher selectivity of rilmenidine for imidazole to alpha 2-adrenoceptors as compared to clonidine may explain the lower sedative effects of rilmenidine.
pubmed:language
eng
pubmed:journal
pubmed:citationSubset
IM
pubmed:chemical
pubmed:status
MEDLINE
pubmed:month
Mar
pubmed:issn
0014-2999
pubmed:author
pubmed:issnType
Print
pubmed:day
26
pubmed:volume
195
pubmed:owner
NLM
pubmed:authorsComplete
Y
pubmed:pagination
181-91
pubmed:dateRevised
2007-11-15
pubmed:meshHeading
pubmed:year
1991
pubmed:articleTitle
Rilmenidine lowers arterial pressure via imidazole receptors in brainstem C1 area.
pubmed:affiliation
Department of Neurology and Neuroscience, Cornell University Medical College, New York, NY 10021.
pubmed:publicationType
Journal Article