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PredicateObject
rdf:type
lifeskim:mentions
pubmed:issue
5
pubmed:dateCreated
1998-2-3
pubmed:abstractText
1. A loud acoustic stimulus was administered to rats prior to and after treatment with autonomic blockers in order to unravel the autonomic mechanisms of the blood pressure (BP) and heart rate (HR) responses to startle. 2. Six rats, implanted with a BP telemetric system, were used in a randomized crossover saline-controlled (saline vs. autonomic blocker) study with a washout period of 7 days between each active session. A first acoustic stimulus (110 dB, 0.7 s) was administered. An autonomic blocker i.e. atropine methylnitrate (15 mg. kg-1), atenolol (15 mg. kg-1) or prazosin HCl (1 mg. kg-1), or physiological saline was administered i.p. 40 min prior to a second identical acoustic stimulus. 3. The average BP rise following the first stimulus was +25 mmHg and the average HR change was +17 bpm. The responses after autonomic blockades were affected as follows: atropine increased the HR rise (+45.1 +/- 1.7 bpm), atenolol reversed the HR changes to a bradycardic response (-21.4 +/- 9.1 bpm), after prazosin treatment the BP rise was reversed into a BP decrease (-11.3 +/- 3.2 mmHg) and the HR increase was amplified (+76.0 +/- 10.0 bpm). Finally, the delay for obtaining the maximal BP change was increased from 1.9 to 2.6 s following prazosin pretreatment. 4. These results indicate that the BP rise resulting from an acute loud noise depends on a vascular sympathetic activation (prevented with prazosin), which is partly blunted by vasodilation (revealed with prazosin). The evoked HR changes combine a sympathetic activation (fully expressed following atropine) and a vagal activation (unmasked with atenolol). Further experiments are necessary to document the vasodilatory component unmasked with prazosin.
pubmed:language
eng
pubmed:journal
pubmed:citationSubset
IM
pubmed:chemical
pubmed:status
MEDLINE
pubmed:month
Oct
pubmed:issn
0144-1795
pubmed:author
pubmed:issnType
Print
pubmed:volume
17
pubmed:owner
NLM
pubmed:authorsComplete
Y
pubmed:pagination
303-9
pubmed:dateRevised
2007-11-15
pubmed:meshHeading
pubmed-meshheading:9427109-Acoustic Stimulation, pubmed-meshheading:9427109-Adrenergic alpha-Antagonists, pubmed-meshheading:9427109-Animals, pubmed-meshheading:9427109-Atenolol, pubmed-meshheading:9427109-Atropine Derivatives, pubmed-meshheading:9427109-Autonomic Nerve Block, pubmed-meshheading:9427109-Autonomic Nervous System, pubmed-meshheading:9427109-Blood Pressure, pubmed-meshheading:9427109-Evaluation Studies as Topic, pubmed-meshheading:9427109-Evoked Potentials, Auditory, pubmed-meshheading:9427109-Heart Rate, pubmed-meshheading:9427109-Hemodynamics, pubmed-meshheading:9427109-Male, pubmed-meshheading:9427109-Parasympatholytics, pubmed-meshheading:9427109-Prazosin, pubmed-meshheading:9427109-Random Allocation, pubmed-meshheading:9427109-Rats, pubmed-meshheading:9427109-Rats, Wistar, pubmed-meshheading:9427109-Sympatholytics
pubmed:year
1997
pubmed:articleTitle
Autonomic components of the cardiovascular responses to an acoustic startle stimulus in rats.
pubmed:affiliation
Department of Pharmacology, CNRS URA1482, Fac. Medicine Necker, Paris, France.
pubmed:publicationType
Journal Article